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IT Made EZ – Episode 3: Troubleshooting a Network

Welcome to IT Made EZ where we take you from zero to proficient in information technology focused on a helpdesk position.

Check out the video and take the quiz below to see what you’ve learned!

If you prefer to read instead of watch videos, you can read the entire script below the video.

We’re going to start with the modem. The main symptom with a modem problem is everyone in the company being unable to access the internet, webpages loading very slowly and frequently timing out, or some websites simply don’t load at all.

  • No matter how far we come with technology, I don’t think we’ll ever get past simply unplugging something and plugging it back in as a first troubleshooting step.
  • Sometimes it’s difficult to determine if the problem is with your modem or your router, so power-cycling both devices is usually recommended.
  • If the internet still doesn’t come back up, try plugging a laptop directly into the modem. The computer will most likely grab a public IP address, but if you can browse the internet, the issue is probably not the modem. If the internet doesn’t work properly from the laptop, go to a website like from your cell phone to see if your provider has any known outages in your area. If you see that multiple people in the area have a problem, your best bet is to just wait it out. Chances are, they’re already working on it and no, they don’t have any clue when you’ll be back online. If your business relies heavily on the internet, it’s best to have a backup connection with a different provider. Unless there’s a major power outage in the area, the odds of both providers being down at the same time is slim. Some connections can even come from cellular towers which are pretty reliable even in a storm, but the bandwidth isn’t usually fast enough to run an entire business. If there doesn’t appear to be an ISP outage but the modem simply won’t connect, call the provider’s tech support and they can walk you through additional troubleshooting steps. I recommend renting a modem from an ISP rather than buying one on your own, because they will almost always point the finger at equipment they don’t have control of when problems arise. If it’s their modem, they have all the access they need to run diagnostics and can often determine the problem faster.

As for the router, sometimes settings can become corrupted. If everything looks correct but the router refuses to connect to the modem, you could try backing up the settings and doing a factory reset. Yes, that might be time-consuming if there are a lot of custom settings, but a replacement could be very expensive depending on how powerful the unit is.

Moving onto switches. A problem with a switch will present itself as more than just an internet issue. Connectivity to everything on the network will be affected such as software, printers, and mapped drives. If multiple people have network connectivity issues at the same time, the switch is almost always to blame. If only one person or a small group of people have a problem, make sure there isn’t a 5-port switch hidden under a desk somewhere. If there is, maybe it died or simply needs to be power cycled. If you can’t get it working, try bypassing the switch to make sure the connection from the wall jack is working. Also, don’t forget to try a different cable if you’re still having trouble. If the wall jack isn’t working, the wires inside might be loose, the wires inside the patch panel could be loose, the cable that plugs into the switch in the equipment room could be bad, or one of the ports on the switch could have died.

Another common switch issue that’s important to know about is called a loop. This is when a switch is plugged into itself. When that happens, most if not all of the network will be down or at the very least, unusable. Sometimes equipment is removed, but the ethernet cable is left plugged in, dangling from the switch. Then someone comes along and decides to plug it in without realizing that the other end is already plugged in. That’s just the most obvious way to create a loop. My favorite loop story is from a company that had two network jacks on the wall, and also had a phone with two network jacks in it. I think you know where this is going. They plugged an ethernet wire into both ports on the phone and thus created a loop that wasted lots of time and money. The intention with that phone design is for you to plug the phone into the network, and then plug your computer into the phone, thus needing only one network connection at each person’s desk and avoiding the need for a 5-port switch or additional wiring.

Now let’s tackle server issues. Because we focus on helpdesk, we’ll only discuss problems from the end user perspective.

We mentioned IP conflicts in our last video, but it’s not always obvious when they’re occurring. If a computer is struggling to grab an IP address or communication isn’t working properly, try creating a DHCP reservation so it grabs a specific IP address that you know is available. Updating the network card driver is also a good thing to try. I’ve also seen issues where a computer will refuse to obtain an IP address automatically, but manually entering network settings allows connectivity. Maybe it’s a symptom of a hardware problem or mild OS corruption, but it’s not always worth the time to fully rectify the situation if there is a reasonable workaround. Just don’t forget to create a DHCP reservation if you do end up keeping manual network settings on the computer.

DNS is also handled by the server if the network has a domain controller. If a PC cannot talk to your local domain, make sure the DNS server is correctly configured.

You can find your DNS settings two ways. Open a command prompt and type ipconfig and then a space followed by a forward slash and then the word “all”. This will display your IP address along with the IP responsible for DHCP and DNS. You can also enter ncpa.cpl in a run box, right-click the active network interface, and click on Status. The details button will show you everything you need to know about the computer’s network information. The ping command is also super helpful when it comes to troubleshooting DNS issues. Make sure you know what a hostname should resolve to, and then check to see if the correct address is responding.

Active Directory is next on the list, so we’ll start with the most common issue of passwords. If someone has a laptop at home when their password is scheduled to expire, they will not be able to update the password without connecting to a VPN, because the Domain Controller stores all the passwords and needs to know about any changes. Once the password is updated on the domain, you can disconnect the VPN as the new credentials will then be cached on the laptop.

It’s important to note that a laptop should only be joined to a domain if the user occasionally brings it into the office, say…once a week or no less than once every two weeks. Otherwise, you run the risk of the domain losing its relationship with the laptop. The user goes to log into their laptop one day, and they’re presented with a Domain Trust Relationship error message which refuses to let them into the computer. The fix is logging in as a local administrator, disjoining the domain, rebooting, and then rejoining the domain. To do so, click on Other User and then put a period in the username field followed by a backslash. This will change what it says next to “Sign in to” and the computer name will replace the domain name. Honestly, I’ve seen the Domain Trust Relationship error happen randomly even on a computer that’s in the office 100% of the time so make sure you have the local admin password documented somewhere. The only other way to get into the local admin account if you don’t know the password is with a boot disc exploit, but it’s not possible to do this remotely. You would need to be in front of the laptop to boot into Windows install media.

Another issue you could run into with a non-domain laptop using matching credentials is having the correct password on the domain and on the laptop, but there is an incorrect password cached in the Credential Manager. If browsing to the network prompts for credentials and you know the laptop account matches the domain account, open up the Credential Manager and clear any relevant entries from the Windows Credentials side.

Another issue in Active Directory is one you will only see if you try to copy an existing user when creating a new account if the company users Microsoft 365 to host email. You might see an error message that says, “the name reference is invalid”. This can be fixed by opening the Attribute Editor tab on the Active Directory account you want to copy. The Attribute Editor will only be visible if Advanced Features are enabled in the View menu in Active Directory and if you’re not viewing an account from the search results. Open the account in question and scroll down to “ShowInAddressBook”. Double-click and remove all of the entries shown. You will then be able to copy the user account which will save time if there are a lot of Security Groups they need to be added to. If you’re having trouble locating the actual user account, right-click the domain name and choose Find. Do your search and then click on View > Choose Columns. Find Distinguished Name in the Columns available list, click Add, and then click OK. This will show you the full path to the user account, listing all of the OUs that it could be buried under.

Here’s one additional tip for changing users on a computer when the organization is using Microsoft 365. Open an Office product like Excel and click on File > Account. On the left side of the screen, click “Sign out” until no account is shown. Then close and reopen Excel. You should then be prompted to “sign in” which will license the Office suite for the new user.

As for mapped drives, if someone has no network drives in Windows Explorer or didn’t receive an update like everyone else did, open up command prompt and type gpresult followed by a space, a forward slash, and then the letter R. This will tell you what Security Groups the user is a part of as well as what policies were applied and which may have been filtered out. If you get a message that says “No user data in R-S-O-P”, there is a relationship problem with the domain. Disjoin and rejoin the domain to rectify the issue.

And now for a brief word about printers (Darth Vader “Nooo”) One of my co-workers likes to joke that if he ever quits IT someday, it will be because of printers. Personally, I don’t think they’re that bad. However, I’m going to cover them more in-depth in the next video, so I’ll just skip them for now.

Moving onto wireless issues. Wi-Fi is everywhere these days, so everyone takes it for granted. However, some older devices may refuse to connect to newer Access Points due to the protocols in-use. It’s always a good idea to stay current with Wi-Fi drivers on your laptop if possible. If Wi-Fi won’t connect for one specific device, one troubleshooting step is to have the device forget the network and attempt reconnection. If that doesn’t work, sometimes the Access Point needs to be power cycled even though only that one device won’t connect. If a laptop is really old and you already have the latest Wi-Fi driver available, your only option would be a third-party USB Wi-Fi adapter as it would use more current protocols.

Misc. network equipment. I have a fun story for that, too. Someone had an HVAC controller on their network that stopped communicating and they claimed there was no way to power cycle the system. They also had no support on the unit as the company didn’t service them anymore. I opened up the panel on the circuit board and took the Tony Stark approach (Iron Man “this looks important”). I found what appeared to be giving the board power and removed it for a few seconds. Sure enough, it came back to life shortly after plugging it back in. So remember, troubleshooting step number one is almost always to reboot it somehow.

Now let’s talk about VPN. The most common issue with setting up a VPN for the first time is someone’s home network scope matches their office network scope. For example, both of their networks might start with 192.168.1. Therefore, if you try to communicate with something on the work network, your home computer is going to think that you’re trying to talk to your home network and never reach the intended destination. Fortunately, it’s pretty easy to change the scope of a network on a home router provided that you can log into it. I’ve never seen more than a simple power cycle needed to reconnect a device after a scope change.

Another issue with a VPN is slow or unreliable internet connections like we mentioned in the last video. Unfortunately, sometimes that is out of your control and it would be better if someone left their computer at the office and remoted into it from a home PC or Mac using RDP. If VPN is absolutely necessary, all you can do is recommend that the person call their ISP and upgrade their bandwidth.

Common RDP issues can be caused by Windows Firewall being on and not having Remote Desktop excluded. RDP is also disabled by default, so someone may have forgotten to turn it on. Also, the IP address of the computer may have changed, and DNS didn’t update on the server. To solve that problem, launch DNS on the server, find the destination computer in the list, and manually update the IP address to the correct one.

Once RDP is connected, the problems don’t always end there. Sometimes the screen will appear too small if your home computer is Windows 10 and the destination computer is still Windows 7 or a Terminal Server running Windows Server 2012 or older. Windows 10 handles large screen resolution sizes by turning up the DPI scaling. However, DPI scaling doesn’t work in RDP unless the destination is Windows 10 or Windows Server 2016 or newer. Therefore, the native resolution of your home computer will be used, and everything will look tiny because you might have a 4K or 8K resolution monitor on your home computer. Totally necessary, right? Anyways, there’s two things you can do in this situation. One is a registry tweak that allows custom DPI scaling in an RDP session for a Windows 7 computer as the destination. Another is to calculate your actual screen resolution. To do so, take the scale percentage and move the decimal point two places to the left. For example, 150% scaling would be 1.5. In your calculator, divide your screen resolution dimensions by 1.5 and you’ll get your native resolution. However, the end result might not be a common screen resolution. Fortunately, some video cards allow you to create a custom resolution. If yours doesn’t have that feature, the Windows 10 Microsoft Store has an Intel Graphics Command Center Beta app which allows you to create a custom screen resolution even if your video card doesn’t directly support it. Honestly, sometimes it’s just best to go with a slightly smaller or slightly larger screen resolution if that would give you a more common set of dimensions like 1600 x 900 or 1920 x 1080.

It’s also important to note that webcams don’t work inside an RDP session. The best-case scenario is to load Microsoft Teams or whatever video conference software is needed directly onto someone’s home computer so it can use their webcam directly. It is possible to use a webcam’s microphone inside RDP as long as it’s enabled in the config. To do so, right-click the RDP config and choose Edit. Then go to the Local Resources tab and click Settings. Make sure “Record from this computer” is selected under Remote audio recording. Close and reopen the RDP session, and a microphone should then be available to use in all remote software.

The last thing I’ll mention is the annoyance of unwanted startup items that get launched when you first log into your computer. Task Manager has the ability to show you some software that runs at startup, but there could be more that’s not visible in that tab. I recommend using third-party software called CCleaner which can show you everything else and also gives you lots of options to remove temp files and other unnecessary data on your computer.

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