Switch and Router Configuration Validation with Wireshark

 

I get involved in a lot of network migration or installation projects.

In some cases, I am not responsible for configuring the equipment, nor do I have access.

Regardless who configured the equipment, I always take a sample trace before I do anything to confirm how the device is configured. For example:

-          Is DHCP configured correctly

-          same point for DHCP forwarders or ip helper addresses

-          am I on the correct vlan

-          can I access networks that are allowed?  Or blocked

-          is DNS working properly

I’m sure you get the idea

In this video I test to ensure that the vlan I’m connected to is behaving as expected as well as the router/DHCP server.  Its literally a 2 min video, the point being these tasks do not take a long time.

Google Search tip "site:"

 

As I mentioned in the video, some clients are surprised when I show them tips and tricks that help me in my sessions or when troubleshooting.

In this example I use the search term "site:" to search for specific words in specific sites. for example, password site:thetechfirm.com will search for the word "password" in thetechfirm.com site

Determine Your WAN IP with one Powershell command

 Since I get a lot of positive feedback from my short videos and articles......

Her is one PowerShell command to display your WAN IP:

(Invoke-RestMethod -Uri 'http://ipinfo.io/json').ip

the output will look something like this

another way is using wget

wget http://myexternalip.com/raw -O myip.txt

and your ip address will be in myip,txt

Testing My Edgerouter's load balancing

 

If you’ve ever attended any of my sessions, you probably heard me say 1,000,000 times “test, test, test!”

You probably also heard me say “you never learn much when things go right”

Both of these comments are very closely related.  The point is, if you’ve ever installed anything and never had an issue, you don’t learn too much.  I know that sounds odd but you have issues, you have to work your way through it and you learn a tremendous amount about the equipment and the configuration.

In this video, I walk you through a load balancing verification exercise I did for a client.  They have two Internet links and I wanted to be sure that when the connection failed the other would pick up the load accordingly.

I also wanted to find out how long it took for this process to happen as well as the various commands the helpdesk and use to figure out if this was in fact happening.

In this example, much like many examples the primary link has a faster speed than the backup link.  Many times the back up LINK ends up as the primary, and nobody ever notices is until someone mentions that things seem a bit slow.

As I mentioned in the video, it doesn’t matter if you’re the same equipment as I do, just pay attention to the methodology and tools that I use.

Link to hrping

https://cfos.de/en/ping/ping.htm

 

Ubiquiti commands I used

show load-balance status

show ip route

traceroute 8.8.8.8

set interfaces ethernet eth8 disable

show load-balance status

show ip route

traceroute 8.8.8.8

delete interfaces ethernet eth8 disable

show load-balance status

show ip route

traceroute 8.8.8.8

How to Setup TCP Tunneling with Rustdesk

 

Why ‘Tunnel’?

In this example, tunneling is more of a relay or a proxy. I’m using my favorite remote desktop software called Rustdesk. With it, I can use its tunneling feature. That allows me to map a TCP Port on one side and I will end up on the far side of the remote PC's network.

I like this feature because during a network issue, having a lot of data and graphics redrawn on the screen, can take a while. when I use the tunneling feature, I can use my local web browser, terminal emulator or software and the tunneling acts like a vpn connection.

If this is hard to visualize, check out the short video.

Rustdesk https://rustdesk.com/

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