November 18, 2025 • 30 mins
The everyday internet feels effortless, but behind every click lives a maze of services quietly doing the heavy lifting. I pull back the curtain on the systems that make your workday possible—file shares that just appear on your desktop, printers that hum along until a 200‑page PDF wrecks the queue, and the alphabet soup of protocols that move data safely and fast.
We start with the essentials: SMB and Samba for file and print, why SFTP on port 22 beats FTP for modern transfers, and how relational databases differ from NoSQL when your needs shift from consistent records to massive logs. From there we head to the browser, unpacking HTTPS, TLS, and certificates so you know what that lock icon actually guarantees. Email gets its due too: SMTP for sending, IMAP for syncing, and the trio of SPF, DKIM, and DMARC that keeps phishing at bay.
Security and scale meet in the middle with proxy servers, spam gateways, and Unified Threat Management devices that filter, inspect, and sandbox threats before users ever see them. Then we look at load balancers that keep portals alive at peak times, plus the messy reality of legacy systems that refuse to retire. We don’t ignore the industrial world—embedded devices, ICS, and SCADA that run utilities and factories—where one misstep can ripple beyond a single office.
Troubleshooting ties it all together. I share real stories and checklists for wired faults, slow networks, Wi‑Fi ghosts caused by microwave ovens, and VoIP glitches fixed with QoS and VLANs. You’ll leave with practical ways to spot the root cause fast, confidence with ports and protocols, and a clearer map of the services that keep everything running.
If you learned something useful, follow the show, share this episode with a teammate, and leave a quick review to help others find us. Got a strange network mystery you solved? Send it my way and we’ll feature the best ones next time.
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Listen on: Apple Podcasts Spotify
Art By Sarah/Desmond
Music by Joakim Karud
Little chacha Productions
Juan Rodriguez can be reached at
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@Prof_JRod
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Transcript
Episode Transcript
Available transcripts are automatically generated. Complete accuracy is not guaranteed.
SPEAKER_00 (00:28):
And welcome to Technology Tap.
I'm Professor J.
Rod.
In this episode, UnderstandingNetwork Services, let's tap in
(00:49):
the UK.
Welcome back to another episodeof Technology Tap, the show
(01:11):
where we keep tapping intotechnology and unpack the things
that make our digital world runquietly, efficiently, and most
of the time without you evernoticing.
I'm your host, Professor J.
Rod, and today we're diving intosomething that most people never
even think about, but absolutelycan't live without.
That's network services.
(01:32):
If the internet were a city,there would be street lights,
the traffic cops, the watersystems, the subway lines, all
the infrastructure that keepseverything moving.
You don't see them, you don'tinteract with them directly, but
without them, chaos.
And that's what today's episodeis about.
No reading slides, no roboticdefinitions, just conversation.
You and me.
(01:52):
So grab your cup of coffee, grabyour notebook, and let's begin.
Network hosts services, theservices you never see, but you
always use.
Let me start with a visual.
Imagine it's 8 03 a.m., anoffice in downtown Manhattan.
Employees walking in withcoffee, scanning their badges,
logging into their PCs.
(02:14):
Someone goes to print out aweekly report.
Someone else pulls up the lastquarter's financial spreadsheet
from the share drive.
Another person opens the HRportal to check their benefits.
Nobody thinks, hmm, which serveris handling this?
Nobody says, is it SMB?
Is it Radius?
Am I authenticating via LDAP?
(02:34):
Nope.
They just expect it to work.
But behind the scenes, networkservices are firing like neurons
in the human brain.
Let's walk through them.
File and print servers.
I always start with this becauseit's the simplest to visualize.
When you click on a folder on ashared drive and you map and
(02:56):
your map to let's say a server,right?
A file server, right?
That's what you're tapping into.
You're tapping into a fileserver.
There's a machine, often apowerful one, that stores files
centrally so that the usersacross the network can access
them.
And here is where the protocolscome in.
(03:16):
SMB server message block.
SMB is the king of Windows filesharing.
Every time you map a networkdrive, every time you pull a
Word document from the share,SMB is doing the work.
And if you're in a mixenvironment, Linux talking to
Windows, or vice versa, that'swhere Samba comes in.
(03:37):
It's the glue.
Now add printing to the mix.
You send a print job, the servercues it and then pushes it to
the network printer.
Simple, right?
Until somebody prints a 200-pagePDF and installs the print queue
for the entire office.
Then suddenly everybody caresabout the print server.
I always joke.
(03:58):
A print server only becomesfamous when it breaks.
So it it's the port number forSMB is 4.
It's let's see.
It's 445 for SMB.
So you may need that for the ComT exam to know that number.
(04:21):
And for Samba, it is it's still445.
It's the same thing.
So it's 137 to 139 for NetBIOS,but that's an old one.
We haven't used NetBIOS sincethe 1990s.
So you're you're good with that.
Then you got FTP, FTPS, andSFTP.
(04:44):
Now FTP, it's an old schoolplain text, don't use it unless
you're in a sandbox sandbox lab,port number 2021.
FTPS is FTPS plus TLSencryption.
That is uses port number also21.
And SFTP, it's it's weird thatthey use the same port number.
(05:06):
SFTP runs over SSH encrypted,it's secure, modern, and that
port number is 22.
If your job is to remote fileuploads, websites, website
files, firmware updates,configuration backup, SFTP is
what you want, period.
Real world example, a smallbusiness web developer uploads
(05:29):
updated HTML files to thehosting server every week using
SFTP.
Secure, encrypted, no passwordflying around in plain text.
Database servers.
Now picture Amazon or Netflix oreven your college registration
system.
Every login, every productsearch, every streaming queue,
they all come for the databaseserver.
(05:50):
Let me break it down supersimple.
You have your flat files, CSVfiles, Excel sheets, very basic.
Then you have your relationaldatabase, SQL.
Tables, rolled columns, highlyorganized.
Example, my SQL, MariaDB,Microsoft SQL Server, Oracle.
Then you have yournon-relational No SQL, think big
(06:12):
data, massive scheming, schemalist, perfect for logs, sensors,
internet of things.
Example, MongoDB or CouchDB.
So here's an analogy.
A relational database is like afiling cabinet with perfectly
labeled folders.
No SQL is more like an inboxfull of receipts.
You dump everything in there andyou organize it later.
(06:35):
Real role scenario, a collegestudent stores, a college stores
students' registration info,names, grades, transcript, and a
relational database.
But the millions of log entriestracking login events and
security events that goes intoan No SQL.google.com, what
(06:58):
happens?
Your browser sends an HTTPSrequest to a web server.
The server responds with the webpage.
Simple, right?
Except there are two ways to doit, right?
This eight, there's port 80,which is HTTP, and there's port
443, which is HTTPS, is HTTPencrypted with TLS.
(07:20):
This is where the certificatescome in.
You know that little lock iconnext to a website, which I don't
really see it anymore, but itused to be there.
That's a certificate authorityverifying the website's
identity.
And this started because Google,this is really is really good is
enforced by Google.
(07:40):
If you don't have HTTPS on yourpage, it lowers your ranking.
So if you're selling shoesonline and your website is not
HTTPS, nobody will ever find itbecause they bury you deep in
the searches.
Because you're not secure.
They want everybody secure.
(08:01):
Alright, I once had a studentwho thought HTTPS meant the
website was safe.
I said no.
It means the connection isencrypted.
A scam site can still haveHTTPS.
And that changed how he viewedthe web forever.
Then you have mail servers andmailbox servers.
(08:22):
Every time you send an email,you probably don't think about
ports or protocol, but theserver does.
Sending email is SMTP singlemail transport protocol, port
25.
That's the old one.
We use now SMTPS, port 465 or587.
That's secure.
That's just for sending emails.
Receiving emails pop three.
(08:44):
Post office protocol port 110 isthe old and 995 is the new one.
Download and removes messages.
This is the old way of doingemail where it downloads from
the server to the device thatyou have and it's kept on the
device.
It's not kept on the serveranymore.
Right?
It removes the message from theserver.
(09:04):
So it just downloads.
And then IMAP port 143, a newone is 993, syncs across
devices.
This is what we normally use nowfor like Google and Outlook,
right?
The email gets stored on theirserver, and we can look at it on
our phone and look at it, on ourcomputers and look at it, on our
laptops and look at it, theemail's still there.
(09:26):
If you check your email on bothyour phone and laptop and
everything matched perfectly,that's IMAP.
Authentication, LDAP Radius,Tactius Plus.
This is where things get spicy.
Every time a student logs intotheir college, the username and
passwords get sent to a Radiusserver.
Every time a company employeelogs into a domain computer,
(09:47):
that authentication checks LDAP.
You have your AAA,authentication, authorization,
and accounting.
This is the Holy Trinity.
It answers who are you?
What are you allowed to do?
And what did you do for loggingpurposes?
Radius is used for Wi-Fi logins,centralized authentication.
(10:08):
TACAX Plus is used for devicemanagement, routers, switches,
and firewalls.
Example is a network admin logsinto a Cisco switch.
TACAX logs every command hetypes.
Accountability is on point.
(10:50):
Next, we go to internet andembedded appliances.
When devices start thinking forthemselves and start talking
behind your back.
Alright.
Take a breath, sip that coffeebecause now we are going to walk
through a live IT environment.
We're leaving the comfort of theclassic file print web server
(11:10):
world and stepping into thefront lines of modern
networking.
With proxy servers, spamgateways, unified threat
management, load balancers,legacy systems, embedded systems
in ICS, SCADA, IoT, and smartdevices.
This is where traditional ITmeets the internet, meets
automation, meets security,meets some occasional chaos.
(11:31):
Let's jump in.
Proxy server, the middleman withall the power.
Let me take you back to one ofmy early campus IT consulting
days.
There was a high school studentthat called me because students
were, there was a high schoolthat called me because students
were getting around the contactfilters when you guessed it, VPN
apps.
The school had a firewall, butthey didn't use a proxy server.
(11:54):
Walking into the building feltlike walking into a scene from a
spy movie.
Kids whispering about IPaddress, Chrome extensions,
secret URLs.
Every student was a James Bondvillain in training.
A proxy server will fixeverything.
So what is proxy?
Imagine you're at a restaurant.
Instead of ordering directlyfrom the kitchen, you give the
(12:16):
order to the waiter.
The waiter filters, approves,and handles your request.
A proxy server is the waiter.
When you visit a website, yourrequest goes to a proxy.
The proxy decides if it'sallowed.
Then the proxy fetches the siteand sends it back.
What are the real-worldfunctions of this?
Content filtering, blockingYouTube, social media, adult
(12:38):
content, caching, savingbandwidth by storing common
pages, traffic logging.
Admins can see who visits what.
(13:02):
They cut the bandwidth usage inhalf.
Employees were mad, the ownerwas thrilled.
Balance in the universe wasrestored.
Next, we're gonna talk aboutspam gateways and UTM, your
email sponsor, and yournetwork's bodyguard.
Email is the wild, wild west ofthe internet.
(13:24):
If the internet were a country,email will be the border
crossing where you must showyour passport, and every scammer
and bot tries to sneak inthrough with a fake ID.
Sounds very topical.
Spam Gateway, this is a systemthat checks incoming mail before
it even reaches your inbox.
It's looking at senderreputation, IP address, known
(13:44):
malware signatures, keywords,attachments, known phishing
domains, and something calledSPF, DKM, and DMARC DMARC.
Not the DMARC that's in your ISPequipment.
Not that SPF verifies thesending server is allowed.
(14:05):
DKIM digital signature to ensuremessage integrity and DMARC
tells server what to do if themessage fails checks.
Think of it as SPF being are youon the guest list?
And DKIM being is your ID legit?
And DMARC, if your ID fails,kick them out or send them to
spam.
(14:26):
Unified threat management.
Now this one's the beast.
A UTM is basically the SwissArmy knife of security
appliance.
It does firewall, antivirus,anti-malware, IDS, IPS, web
filtering, VPN, sandboxing.
All bundled into one device.
Real roll story.
There was a dentist office Ivisited once, small, maybe 10,
(14:50):
12 desktops.
They had a basic router, nofirewall, no antivirus, Windows
XP running on one machine.
Yes, Windows XP.
Doctors checking Gmail on thestate network as patients'
medical records, a single UTMbox fixed almost everything.
When I installed it, the ownerlooked at me and said, I didn't
(15:11):
know we needed that.
And I said, You didn't know youneeded it through sheer luck
alone.
Load balancers, because oneserver is never enough.
Ever wonder how Amazon handlesmillions of people shopping at
the same time?
Or how Netflix streams tohundreds of thousands of users
simultaneously without breaking?
(15:31):
Or how your college portalcrashes only during registration
week because they don't haveone.
This is where load balancerscome in.
A load balancer sits in front ofmultiple servers and spreads the
work evenly.
Think of it as a tow booth.
One open lane equals a massiveline, ten open lanes equals
smooth traffic.
(15:52):
That's load balancing.
When a web server getsoverloaded, the load balancer
shifts traffic to a less busyserver.
When a server fails, the loadbalancer removes it from the
pool automatically.
Load balancers can even detectslow performance before the
users notice.
A practical example.
(16:12):
Imagine you're running arestaurant, there's one chef in
the kitchen, orders pile up,chaos.
Now imagine you have five chefsand a head chef deciding who
handles which order.
The head chef is your loanbalancer.
Every semester when students tryto visit Blackboard or
BrightSpace at the same time,the system slows down or crashes
(16:32):
because the servers areoverloaded.
If the college students had abetter load balancing plan,
students will complain a lotless.
Legacy systems.
The ancient creatures stillalive in modern networks.
Legacy systems are the dinosaurof IT.
And here's one thing (16:50):
dinosaurs are still alive in some
networks.
End of life.
The manufacturer no longer sellsor updates the system.
End of service life.
No more support, no morepatches, no security updates.
You're on your own.
These systems can be old medicalmachines, manufacturing
equipment, point of salesystems, old government systems,
(17:14):
custom-built software no oneknows how to maintain.
I once walked into the officeand still ran their business on
an old Windows and Windows XPmachine.
They said, We can't replace itbecause the software it turns it
runs doesn't exist anymore.
The machine was their entireoperation.
No backup, no imaging, just purehope.
(17:35):
If the machine failed, that wasthe end of the business.
This is why legacy systemsmatter.
They're risky, but people keepthem alive because replacing
them is an expensive,complicated, or practically
impossible.
Embedded systems in ICS.
Computers that doors that don'tlook like computers.
Now we enter the industrialworld.
(17:57):
Embedded systems.
These are computers built intodevice to perform a very
specific function.
Example, smart thermostat,routers, microwave controllers,
medical machines, car infoinfotainment systems.
They're not meant to forbrowsing the internet or running
Word.
They're built for one job andthey do that job extremely well.
(18:20):
ICS, Industrial Control Systems.
These run factories, powerplants, HVAC, elevator controls,
big, heavy, serious systems.
If a regular PC fails, annoying.
If an ICS fails, worse thingshappen.
Then we have SCADA, the nervoussystems of modern
infrastructure.
(18:41):
SCADA stands for SupervisoryControl and Data Acquisition.
It is a system that monitors andcontrols the entire industrial
environment.
Power grid, water treatmentplants, subway systems, gas
pipelines, these systems areoften distributed across wide
geographical areas, and SCADAties them together.
(19:01):
Real world example.
When you turn on your faucet,there's a water treatment
facility using SCADA to monitorthe pressure, the flow rate, the
chemical balance, the pumpperformance.
It's the quiet hero.
And if SCADA goes down, youdon't want to know what happens.
It's going to be briscible.
That diehard 4 is kind of liketalks about a lot of that.
(19:22):
That movie Die Hard 4.
unknown (19:25):
Alright.
SPEAKER_00 (19:27):
Troubleshooting networks.
When things break, and theyalways do, here's what you do
next.
Okay.
This is where IT becomes realbecause theory is beautiful,
diagrams are clean, and slidesare perfect, but troubleshooting
is messy.
It's part of IT where you're onthe floor behind a desk, someone
(19:50):
is breathing over your shoulder,someone else is saying, I it
worked yesterday and your coffeeis getting cold.
Welcome to Help Desk Life.
Let's go step by step.
Troubleshooting wiredconnection.
If it has a cable, that cablewill betray you eventually.
Wired issues are the foundationof troubleshooting.
No matter how advanced yourenvironment is, at some point
(20:12):
you will crawl under your desk.
That is true.
Let me give you a real story.
I was once called totroubleshoot on Office PC.
Every 10 minutes, connectiondrops, then reconnects, then
drops again.
Classic port flapping.
I checked IP config, switchport, nick drivers, patch panel,
(20:34):
everything looked normal.
Then I saw it.
The internet was pinched underthe wheel of the person's chair.
Every time he rolled back,signal loss.
Every time he rolled forward,connection restored.
That was it.
A$5 cable cost two weeks of helpdesk tickets.
Common wired issues, looseconnection, damaged cable, bent
(20:55):
cable with broken copper pairs,bad nick, speed duplex,
mismatch, incorrect VLANassignments, port security
blocking the device, patch panelmiswiring.
Here's a tip always inspect thephysical layer first.
50% of the wired issues arephysical.
(21:16):
Troubleshooting network speed.
Slow internet is the fastest wayto people to make people hate
IT.
When a user says the network isslow, this can mean 20 different
things.
(21:42):
While they were on Zoom, evenNASDAQ can help you with that
one.
Real cost of slow networkspeeds, port misconfiguration.
Switch port is set to 100megabytes, but a NIC but the NIC
supports 1GB.
Bad cabling, Cat 5 instead ofCat 6, or damaged copper, or
cable runs that exceed 100meters.
(22:04):
Interference, fluorescentlights, microwave, old power
cables, even fish tanksinterfere.
Malware, a compromised PCsending backward traffic can
slow everything.
Saturations, too many devicestreaming or one user hogging
bandwidth.
Next, troubleshooting wirelessissues, Wi-Fi, the thing
(22:25):
everyone uses but nobodyunderstands.
Wireless issues are trickybecause radio waves don't obey
workplace rules.
They go through walls, aroundcorners, into ceilings, into
stairwells, or just disappear.
I was once on the 13th floor ofa building and I can get the
Wi-Fi from across the streetfrom the deli.
(22:46):
He had it on open for years.
For years he had it open.
And we used to watch Netflix.
That's when Netflix went onstreaming.
A company once had a Wi-Fi ghostzone.
Every afternoon, one section ofthe office lost connection.
Same time every day, lockclockwork.
(23:06):
Was it cyber attacks, sunspots,ghosts, chaos three?
Nope.
At 2 p.m.
An employee on break plugged intheir own portable microwave and
heated up above leftoverspaghetti.
2.4 gigahertz interference.
Microwave on, Wi-Fi dead.
Microwave off, Wi-Fi restored.
Case closed.
(23:26):
Common Y wireless problems, poorsignal, users too far from the
access point.
Ban selection, a device on 2.4,but the access point is set to 5
GHz only, no connection.
Mismatch Wi-Fi standards, user'slaptop only supports 802.11N,
but the network forces 802.11AC.
(23:47):
Channel overlap, specificallywith 2.4, device interference,
microwaves, coreless phones,baby monitors, smart TVs.
Incorrect security settings, APuses WPA3, but device can only
authenticate via WPA2.
Roaming aggression, devicerefused to switch to better APs.
(24:08):
Troubleshooting VoIP, voiceoverIP.
Voice over IP is amazing untilit glitches.
VoIP has three enemies latency,jitter, and packet loss.
Latency is delay in audio.
Jitter is variation in delay,causes choppy audio.
Packet loss, audio drops.
(24:28):
I heard a story once about a guyworking at a call center once
when the agent complained, Ihear the customer fine, but they
hear me underwater.
Turns out the office next doorinstalled the massive new
network printer on the sameswitch as the call center's VoIP
phones.
Every time somebody printed, itconsumed bandwidth and caused
jitter.
Solution (24:46):
Move the printer to a separate VLAN and prioritize
VoIP traffic with quality ofservice.
Clear call instantly.
Troubleshooting limitedconnectivity.
The dreaded connected nointernet message.
This is an iconic Windowsmessage that haunts people
everywhere.
Common causes wrong IP, wrongsubnet mask, wrong gateway, DNS
(25:10):
not responding, DHCP scopeexhausted, duplicate IP, block
port.
Quick story.
(25:36):
Alright, wrap up.
The invisible world becomesvisible.
We covered host services, webmail authentication, proxy and
filtering, Internet of Things inSCADA, load balancing, wireless
wireless troubleshooting, VoIP,and VLANs.
Now, on to the questions.
Everybody's favorite topic orsection of the podcast.
(26:01):
Alright, I read the question,give you the choices, read it
back.
You give me this the answer.
Question one (26:07):
a user reports slow internet during lunchtime.
The most likely cause is Aincorrect DNS servers server, B
network saturation, C wrongsubnet mask, D DACP lease
expiration.
Again, a lease a user reportsslow internet only during
(26:28):
lunchtime.
The most likely cause is Aincorrect DNS server, B network
saturation, C wrong set subnetmask or D DACP lease expiration.
It's not giving you a lot.
This question doesn't give you alot to go on.
But I'll give you five seconds.
Five, four, three, two, one.
(26:48):
The answer is B networksaturation.
Everybody at lunchtime is usingthe internet to watch something,
right?
Maybe la casa de lo, you knowwhat?
Two, a wireless user losesconnection every time they walk
into a conference room.
Signal immediately returns whenthey leave.
The most likely problem is aDHCP failure.
(27:11):
B drop due to interference, Cduplicate IP or D incorrect
VLAN.
A wireless user loses connectionevery time they walk into a
conference room.
Signal immediately returns whenthey leave.
The most likely problem is ADHCP failure.
B drop failure, drop due tointerference, C duplicate IP or
D incorrect VLAN.
(27:32):
I give you five seconds.
Alright, hopefully you're twofor two.
Next, a VoIP system has choppyaudio and robotic voices.
Which issue is it most likely?
(27:53):
A low RSSI B High jitter C wrongDNS or D incorrect gateway.
I'll read it again.
A VoIP system has a Choppy audioand robotic voices.
Which issue is most likely?
A low RSS I B high jitter Cwrong DNS or D incorrect
(28:15):
gateway.
Give you five seconds.
Five, four, three, two, one, andthe correct answer is B high
jitter.
Alright, last one, let's go forfour for four.
A PC plugged into a switch portshows connected, no internet.
Other PCs work fine.
What should the technician checkfirst?
(28:36):
A monitor resolution B duplicatesettings C incorrect IP or D the
keyboard.
A PC plugged into the switchportshows connected no internet.
Other PCs work fine.
What should the technician checkfirst?
A monitor resolution B duplicatesettings C incorrect IP address
(28:56):
or D keyboard.
I'll give you five seconds.
Five, four, three, two, one.
And the answer is C incorrect IPaddress.
All right, that's gonna wrap itup for us today.
Thank you for listening.
The episode on network services,and we hope you learned
(29:18):
something.
And as always, uh keep tappinginto technology, and we'll see
you next time.
(29:47):
This has been a presentation ofLittle Chacha Productions, art
by Sarah, music by Joe Kim.
We're now part of the Pod MatchNetwork.
You can follow me at TikTok atProfessor J Rod at J R O D, or
you can email me at ProfessorJrod Jr.
at gmail dot com.
And welcome to Technology Tap.
I'm Professor J.
Rod.
In this episode, UnderstandingNetwork Services, let's tap in
(00:49):
the UK.
Welcome back to another episodeof Technology Tap, the show
(01:11):
where we keep tapping intotechnology and unpack the things
that make our digital world runquietly, efficiently, and most
of the time without you evernoticing.
I'm your host, Professor J.
Rod, and today we're diving intosomething that most people never
even think about, but absolutelycan't live without.
That's network services.
(01:32):
If the internet were a city,there would be street lights,
the traffic cops, the watersystems, the subway lines, all
the infrastructure that keepseverything moving.
You don't see them, you don'tinteract with them directly, but
without them, chaos.
And that's what today's episodeis about.
No reading slides, no roboticdefinitions, just conversation.
You and me.
(01:52):
So grab your cup of coffee, grabyour notebook, and let's begin.
Network hosts services, theservices you never see, but you
always use.
Let me start with a visual.
Imagine it's 8 03 a.m., anoffice in downtown Manhattan.
Employees walking in withcoffee, scanning their badges,
logging into their PCs.
(02:14):
Someone goes to print out aweekly report.
Someone else pulls up the lastquarter's financial spreadsheet
from the share drive.
Another person opens the HRportal to check their benefits.
Nobody thinks, hmm, which serveris handling this?
Nobody says, is it SMB?
Is it Radius?
Am I authenticating via LDAP?
(02:34):
Nope.
They just expect it to work.
But behind the scenes, networkservices are firing like neurons
in the human brain.
Let's walk through them.
File and print servers.
I always start with this becauseit's the simplest to visualize.
When you click on a folder on ashared drive and you map and
(02:56):
your map to let's say a server,right?
A file server, right?
That's what you're tapping into.
You're tapping into a fileserver.
There's a machine, often apowerful one, that stores files
centrally so that the usersacross the network can access
them.
And here is where the protocolscome in.
(03:16):
SMB server message block.
SMB is the king of Windows filesharing.
Every time you map a networkdrive, every time you pull a
Word document from the share,SMB is doing the work.
And if you're in a mixenvironment, Linux talking to
Windows, or vice versa, that'swhere Samba comes in.
(03:37):
It's the glue.
Now add printing to the mix.
You send a print job, the servercues it and then pushes it to
the network printer.
Simple, right?
Until somebody prints a 200-pagePDF and installs the print queue
for the entire office.
Then suddenly everybody caresabout the print server.
I always joke.
(03:58):
A print server only becomesfamous when it breaks.
So it it's the port number forSMB is 4.
It's let's see.
It's 445 for SMB.
So you may need that for the ComT exam to know that number.
(04:21):
And for Samba, it is it's still445.
It's the same thing.
So it's 137 to 139 for NetBIOS,but that's an old one.
We haven't used NetBIOS sincethe 1990s.
So you're you're good with that.
Then you got FTP, FTPS, andSFTP.
(04:44):
Now FTP, it's an old schoolplain text, don't use it unless
you're in a sandbox sandbox lab,port number 2021.
FTPS is FTPS plus TLSencryption.
That is uses port number also21.
And SFTP, it's it's weird thatthey use the same port number.
(05:06):
SFTP runs over SSH encrypted,it's secure, modern, and that
port number is 22.
If your job is to remote fileuploads, websites, website
files, firmware updates,configuration backup, SFTP is
what you want, period.
Real world example, a smallbusiness web developer uploads
(05:29):
updated HTML files to thehosting server every week using
SFTP.
Secure, encrypted, no passwordflying around in plain text.
Database servers.
Now picture Amazon or Netflix oreven your college registration
system.
Every login, every productsearch, every streaming queue,
they all come for the databaseserver.
(05:50):
Let me break it down supersimple.
You have your flat files, CSVfiles, Excel sheets, very basic.
Then you have your relationaldatabase, SQL.
Tables, rolled columns, highlyorganized.
Example, my SQL, MariaDB,Microsoft SQL Server, Oracle.
Then you have yournon-relational No SQL, think big
(06:12):
data, massive scheming, schemalist, perfect for logs, sensors,
internet of things.
Example, MongoDB or CouchDB.
So here's an analogy.
A relational database is like afiling cabinet with perfectly
labeled folders.
No SQL is more like an inboxfull of receipts.
You dump everything in there andyou organize it later.
(06:35):
Real role scenario, a collegestudent stores, a college stores
students' registration info,names, grades, transcript, and a
relational database.
But the millions of log entriestracking login events and
security events that goes intoan No SQL.google.com, what
(06:58):
happens?
Your browser sends an HTTPSrequest to a web server.
The server responds with the webpage.
Simple, right?
Except there are two ways to doit, right?
This eight, there's port 80,which is HTTP, and there's port
443, which is HTTPS, is HTTPencrypted with TLS.
(07:20):
This is where the certificatescome in.
You know that little lock iconnext to a website, which I don't
really see it anymore, but itused to be there.
That's a certificate authorityverifying the website's
identity.
And this started because Google,this is really is really good is
enforced by Google.
(07:40):
If you don't have HTTPS on yourpage, it lowers your ranking.
So if you're selling shoesonline and your website is not
HTTPS, nobody will ever find itbecause they bury you deep in
the searches.
Because you're not secure.
They want everybody secure.
(08:01):
Alright, I once had a studentwho thought HTTPS meant the
website was safe.
I said no.
It means the connection isencrypted.
A scam site can still haveHTTPS.
And that changed how he viewedthe web forever.
Then you have mail servers andmailbox servers.
(08:22):
Every time you send an email,you probably don't think about
ports or protocol, but theserver does.
Sending email is SMTP singlemail transport protocol, port
25.
That's the old one.
We use now SMTPS, port 465 or587.
That's secure.
That's just for sending emails.
Receiving emails pop three.
(08:44):
Post office protocol port 110 isthe old and 995 is the new one.
Download and removes messages.
This is the old way of doingemail where it downloads from
the server to the device thatyou have and it's kept on the
device.
It's not kept on the serveranymore.
Right?
It removes the message from theserver.
(09:04):
So it just downloads.
And then IMAP port 143, a newone is 993, syncs across
devices.
This is what we normally use nowfor like Google and Outlook,
right?
The email gets stored on theirserver, and we can look at it on
our phone and look at it, on ourcomputers and look at it, on our
laptops and look at it, theemail's still there.
(09:26):
If you check your email on bothyour phone and laptop and
everything matched perfectly,that's IMAP.
Authentication, LDAP Radius,Tactius Plus.
This is where things get spicy.
Every time a student logs intotheir college, the username and
passwords get sent to a Radiusserver.
Every time a company employeelogs into a domain computer,
(09:47):
that authentication checks LDAP.
You have your AAA,authentication, authorization,
and accounting.
This is the Holy Trinity.
It answers who are you?
What are you allowed to do?
And what did you do for loggingpurposes?
Radius is used for Wi-Fi logins,centralized authentication.
(10:08):
TACAX Plus is used for devicemanagement, routers, switches,
and firewalls.
Example is a network admin logsinto a Cisco switch.
TACAX logs every command hetypes.
Accountability is on point.
(10:50):
Next, we go to internet andembedded appliances.
When devices start thinking forthemselves and start talking
behind your back.
Alright.
Take a breath, sip that coffeebecause now we are going to walk
through a live IT environment.
We're leaving the comfort of theclassic file print web server
(11:10):
world and stepping into thefront lines of modern
networking.
With proxy servers, spamgateways, unified threat
management, load balancers,legacy systems, embedded systems
in ICS, SCADA, IoT, and smartdevices.
This is where traditional ITmeets the internet, meets
automation, meets security,meets some occasional chaos.
(11:31):
Let's jump in.
Proxy server, the middleman withall the power.
Let me take you back to one ofmy early campus IT consulting
days.
There was a high school studentthat called me because students
were, there was a high schoolthat called me because students
were getting around the contactfilters when you guessed it, VPN
apps.
The school had a firewall, butthey didn't use a proxy server.
(11:54):
Walking into the building feltlike walking into a scene from a
spy movie.
Kids whispering about IPaddress, Chrome extensions,
secret URLs.
Every student was a James Bondvillain in training.
A proxy server will fixeverything.
So what is proxy?
Imagine you're at a restaurant.
Instead of ordering directlyfrom the kitchen, you give the
(12:16):
order to the waiter.
The waiter filters, approves,and handles your request.
A proxy server is the waiter.
When you visit a website, yourrequest goes to a proxy.
The proxy decides if it'sallowed.
Then the proxy fetches the siteand sends it back.
What are the real-worldfunctions of this?
Content filtering, blockingYouTube, social media, adult
(12:38):
content, caching, savingbandwidth by storing common
pages, traffic logging.
Admins can see who visits what.
(13:02):
They cut the bandwidth usage inhalf.
Employees were mad, the ownerwas thrilled.
Balance in the universe wasrestored.
Next, we're gonna talk aboutspam gateways and UTM, your
email sponsor, and yournetwork's bodyguard.
Email is the wild, wild west ofthe internet.
(13:24):
If the internet were a country,email will be the border
crossing where you must showyour passport, and every scammer
and bot tries to sneak inthrough with a fake ID.
Sounds very topical.
Spam Gateway, this is a systemthat checks incoming mail before
it even reaches your inbox.
It's looking at senderreputation, IP address, known
(13:44):
malware signatures, keywords,attachments, known phishing
domains, and something calledSPF, DKM, and DMARC DMARC.
Not the DMARC that's in your ISPequipment.
Not that SPF verifies thesending server is allowed.
(14:05):
DKIM digital signature to ensuremessage integrity and DMARC
tells server what to do if themessage fails checks.
Think of it as SPF being are youon the guest list?
And DKIM being is your ID legit?
And DMARC, if your ID fails,kick them out or send them to
spam.
(14:26):
Unified threat management.
Now this one's the beast.
A UTM is basically the SwissArmy knife of security
appliance.
It does firewall, antivirus,anti-malware, IDS, IPS, web
filtering, VPN, sandboxing.
All bundled into one device.
Real roll story.
There was a dentist office Ivisited once, small, maybe 10,
(14:50):
12 desktops.
They had a basic router, nofirewall, no antivirus, Windows
XP running on one machine.
Yes, Windows XP.
Doctors checking Gmail on thestate network as patients'
medical records, a single UTMbox fixed almost everything.
When I installed it, the ownerlooked at me and said, I didn't
(15:11):
know we needed that.
And I said, You didn't know youneeded it through sheer luck
alone.
Load balancers, because oneserver is never enough.
Ever wonder how Amazon handlesmillions of people shopping at
the same time?
Or how Netflix streams tohundreds of thousands of users
simultaneously without breaking?
(15:31):
Or how your college portalcrashes only during registration
week because they don't haveone.
This is where load balancerscome in.
A load balancer sits in front ofmultiple servers and spreads the
work evenly.
Think of it as a tow booth.
One open lane equals a massiveline, ten open lanes equals
smooth traffic.
(15:52):
That's load balancing.
When a web server getsoverloaded, the load balancer
shifts traffic to a less busyserver.
When a server fails, the loadbalancer removes it from the
pool automatically.
Load balancers can even detectslow performance before the
users notice.
A practical example.
(16:12):
Imagine you're running arestaurant, there's one chef in
the kitchen, orders pile up,chaos.
Now imagine you have five chefsand a head chef deciding who
handles which order.
The head chef is your loanbalancer.
Every semester when students tryto visit Blackboard or
BrightSpace at the same time,the system slows down or crashes
(16:32):
because the servers areoverloaded.
If the college students had abetter load balancing plan,
students will complain a lotless.
Legacy systems.
The ancient creatures stillalive in modern networks.
Legacy systems are the dinosaurof IT.
And here's one thing (16:50):
dinosaurs are still alive in some
networks.
End of life.
The manufacturer no longer sellsor updates the system.
End of service life.
No more support, no morepatches, no security updates.
You're on your own.
These systems can be old medicalmachines, manufacturing
equipment, point of salesystems, old government systems,
(17:14):
custom-built software no oneknows how to maintain.
I once walked into the officeand still ran their business on
an old Windows and Windows XPmachine.
They said, We can't replace itbecause the software it turns it
runs doesn't exist anymore.
The machine was their entireoperation.
No backup, no imaging, just purehope.
(17:35):
If the machine failed, that wasthe end of the business.
This is why legacy systemsmatter.
They're risky, but people keepthem alive because replacing
them is an expensive,complicated, or practically
impossible.
Embedded systems in ICS.
Computers that doors that don'tlook like computers.
Now we enter the industrialworld.
(17:57):
Embedded systems.
These are computers built intodevice to perform a very
specific function.
Example, smart thermostat,routers, microwave controllers,
medical machines, car infoinfotainment systems.
They're not meant to forbrowsing the internet or running
Word.
They're built for one job andthey do that job extremely well.
(18:20):
ICS, Industrial Control Systems.
These run factories, powerplants, HVAC, elevator controls,
big, heavy, serious systems.
If a regular PC fails, annoying.
If an ICS fails, worse thingshappen.
Then we have SCADA, the nervoussystems of modern
infrastructure.
(18:41):
SCADA stands for SupervisoryControl and Data Acquisition.
It is a system that monitors andcontrols the entire industrial
environment.
Power grid, water treatmentplants, subway systems, gas
pipelines, these systems areoften distributed across wide
geographical areas, and SCADAties them together.
(19:01):
Real world example.
When you turn on your faucet,there's a water treatment
facility using SCADA to monitorthe pressure, the flow rate, the
chemical balance, the pumpperformance.
It's the quiet hero.
And if SCADA goes down, youdon't want to know what happens.
It's going to be briscible.
That diehard 4 is kind of liketalks about a lot of that.
(19:22):
That movie Die Hard 4.
unknown (19:25):
Alright.
SPEAKER_00 (19:27):
Troubleshooting networks.
When things break, and theyalways do, here's what you do
next.
Okay.
This is where IT becomes realbecause theory is beautiful,
diagrams are clean, and slidesare perfect, but troubleshooting
is messy.
It's part of IT where you're onthe floor behind a desk, someone
(19:50):
is breathing over your shoulder,someone else is saying, I it
worked yesterday and your coffeeis getting cold.
Welcome to Help Desk Life.
Let's go step by step.
Troubleshooting wiredconnection.
If it has a cable, that cablewill betray you eventually.
Wired issues are the foundationof troubleshooting.
No matter how advanced yourenvironment is, at some point
(20:12):
you will crawl under your desk.
That is true.
Let me give you a real story.
I was once called totroubleshoot on Office PC.
Every 10 minutes, connectiondrops, then reconnects, then
drops again.
Classic port flapping.
I checked IP config, switchport, nick drivers, patch panel,
(20:34):
everything looked normal.
Then I saw it.
The internet was pinched underthe wheel of the person's chair.
Every time he rolled back,signal loss.
Every time he rolled forward,connection restored.
That was it.
A$5 cable cost two weeks of helpdesk tickets.
Common wired issues, looseconnection, damaged cable, bent
(20:55):
cable with broken copper pairs,bad nick, speed duplex,
mismatch, incorrect VLANassignments, port security
blocking the device, patch panelmiswiring.
Here's a tip always inspect thephysical layer first.
50% of the wired issues arephysical.
(21:16):
Troubleshooting network speed.
Slow internet is the fastest wayto people to make people hate
IT.
When a user says the network isslow, this can mean 20 different
things.
(21:42):
While they were on Zoom, evenNASDAQ can help you with that
one.
Real cost of slow networkspeeds, port misconfiguration.
Switch port is set to 100megabytes, but a NIC but the NIC
supports 1GB.
Bad cabling, Cat 5 instead ofCat 6, or damaged copper, or
cable runs that exceed 100meters.
(22:04):
Interference, fluorescentlights, microwave, old power
cables, even fish tanksinterfere.
Malware, a compromised PCsending backward traffic can
slow everything.
Saturations, too many devicestreaming or one user hogging
bandwidth.
Next, troubleshooting wirelessissues, Wi-Fi, the thing
(22:25):
everyone uses but nobodyunderstands.
Wireless issues are trickybecause radio waves don't obey
workplace rules.
They go through walls, aroundcorners, into ceilings, into
stairwells, or just disappear.
I was once on the 13th floor ofa building and I can get the
Wi-Fi from across the streetfrom the deli.
(22:46):
He had it on open for years.
For years he had it open.
And we used to watch Netflix.
That's when Netflix went onstreaming.
A company once had a Wi-Fi ghostzone.
Every afternoon, one section ofthe office lost connection.
Same time every day, lockclockwork.
(23:06):
Was it cyber attacks, sunspots,ghosts, chaos three?
Nope.
At 2 p.m.
An employee on break plugged intheir own portable microwave and
heated up above leftoverspaghetti.
2.4 gigahertz interference.
Microwave on, Wi-Fi dead.
Microwave off, Wi-Fi restored.
Case closed.
(23:26):
Common Y wireless problems, poorsignal, users too far from the
access point.
Ban selection, a device on 2.4,but the access point is set to 5
GHz only, no connection.
Mismatch Wi-Fi standards, user'slaptop only supports 802.11N,
but the network forces 802.11AC.
(23:47):
Channel overlap, specificallywith 2.4, device interference,
microwaves, coreless phones,baby monitors, smart TVs.
Incorrect security settings, APuses WPA3, but device can only
authenticate via WPA2.
Roaming aggression, devicerefused to switch to better APs.
(24:08):
Troubleshooting VoIP, voiceoverIP.
Voice over IP is amazing untilit glitches.
VoIP has three enemies latency,jitter, and packet loss.
Latency is delay in audio.
Jitter is variation in delay,causes choppy audio.
Packet loss, audio drops.
(24:28):
I heard a story once about a guyworking at a call center once
when the agent complained, Ihear the customer fine, but they
hear me underwater.
Turns out the office next doorinstalled the massive new
network printer on the sameswitch as the call center's VoIP
phones.
Every time somebody printed, itconsumed bandwidth and caused
jitter.
Solution (24:46):
Move the printer to a separate VLAN and prioritize
VoIP traffic with quality ofservice.
Clear call instantly.
Troubleshooting limitedconnectivity.
The dreaded connected nointernet message.
This is an iconic Windowsmessage that haunts people
everywhere.
Common causes wrong IP, wrongsubnet mask, wrong gateway, DNS
(25:10):
not responding, DHCP scopeexhausted, duplicate IP, block
port.
Quick story.
(25:36):
Alright, wrap up.
The invisible world becomesvisible.
We covered host services, webmail authentication, proxy and
filtering, Internet of Things inSCADA, load balancing, wireless
wireless troubleshooting, VoIP,and VLANs.
Now, on to the questions.
Everybody's favorite topic orsection of the podcast.
(26:01):
Alright, I read the question,give you the choices, read it
back.
You give me this the answer.
Question one (26:07):
a user reports slow internet during lunchtime.
The most likely cause is Aincorrect DNS servers server, B
network saturation, C wrongsubnet mask, D DACP lease
expiration.
Again, a lease a user reportsslow internet only during
(26:28):
lunchtime.
The most likely cause is Aincorrect DNS server, B network
saturation, C wrong set subnetmask or D DACP lease expiration.
It's not giving you a lot.
This question doesn't give you alot to go on.
But I'll give you five seconds.
Five, four, three, two, one.
(26:48):
The answer is B networksaturation.
Everybody at lunchtime is usingthe internet to watch something,
right?
Maybe la casa de lo, you knowwhat?
Two, a wireless user losesconnection every time they walk
into a conference room.
Signal immediately returns whenthey leave.
The most likely problem is aDHCP failure.
(27:11):
B drop due to interference, Cduplicate IP or D incorrect
VLAN.
A wireless user loses connectionevery time they walk into a
conference room.
Signal immediately returns whenthey leave.
The most likely problem is ADHCP failure.
B drop failure, drop due tointerference, C duplicate IP or
D incorrect VLAN.
(27:32):
I give you five seconds.
Alright, hopefully you're twofor two.
Next, a VoIP system has choppyaudio and robotic voices.
Which issue is it most likely?
(27:53):
A low RSSI B High jitter C wrongDNS or D incorrect gateway.
I'll read it again.
A VoIP system has a Choppy audioand robotic voices.
Which issue is most likely?
A low RSS I B high jitter Cwrong DNS or D incorrect
(28:15):
gateway.
Give you five seconds.
Five, four, three, two, one, andthe correct answer is B high
jitter.
Alright, last one, let's go forfour for four.
A PC plugged into a switch portshows connected, no internet.
Other PCs work fine.
What should the technician checkfirst?
(28:36):
A monitor resolution B duplicatesettings C incorrect IP or D the
keyboard.
A PC plugged into the switchportshows connected no internet.
Other PCs work fine.
What should the technician checkfirst?
A monitor resolution B duplicatesettings C incorrect IP address
(28:56):
or D keyboard.
I'll give you five seconds.
Five, four, three, two, one.
And the answer is C incorrect IPaddress.
All right, that's gonna wrap itup for us today.
Thank you for listening.
The episode on network services,and we hope you learned
(29:18):
something.
And as always, uh keep tappinginto technology, and we'll see
you next time.
(29:47):
This has been a presentation ofLittle Chacha Productions, art
by Sarah, music by Joe Kim.
We're now part of the Pod MatchNetwork.
You can follow me at TikTok atProfessor J Rod at J R O D, or
you can email me at ProfessorJrod Jr.
at gmail dot com.
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