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Network Monitoring and Problem Solving

I recently downloaded and installed a free networking monitoring application just to check it out. I did this so I could monitor my internet bandwidth and hopefully track which VLANs were responsible for the majority of my internet usage. I didn't really have a problem, I was just curious and I like looking at pretty graphs. However, after installing and running this monitor for a few days I noticed a specific error message returning day after day. At first I just dismissed it because I hadn't really tuned what I wanted to monitor. I was more interested in my bandwidth usage and figured I sort through the error messages as some point and see what I had, but this wasn't a high priority.

We'll today I checked the monitoring system and figured I'd start digging through to see what I had there. First error message was this,

Hmm.. Half Duplex? The HECK would I be running that has a half duplex port? I mean, seriously, it's 2013, what could possibly....OH! I think I know. It occurred to me that I have this BluRay player with those built-in internet apps. We use it to watch Netflix, Hulu and Amazon. It's flaky as heck too. It's not wireless, it actually has an RJ45 Ethernet jack in the back and I have it physically patched in to my guest network (Internet only). It works most of the time but often times it will have problems connecting to the internet, it gets slow, Netflix freaks out, Hulu chokes, etc. I end up having to power cycle it, with mixed results. I just figured the whopping $35 I paid for the unit was providing me with a substandard level of quality, which I was willing to live with considering the price I paid.

Well well WELL, this little bit of unsolicited information might be useful after all. I see that it's port 15 on one of my switches that has the problem. I need to verify that this port is, in fact, that BluRay player. How do I do this? Clearly the thing to do is to consult my wiring documentation and see which device is plugged into which patch panel port, then follow that wire to my switch. However, at some point aliens must have visited my house and snatched up that documentation because I can't seem to find it anywhere... weird right? Anyway, and while I'm a fairly young guy, the idea of folding myself in half to get into the space where I can read the label on the wall jack is not that appealing. So, telnet to the rescue! Because my network monitoring system was able to clearly identify the switch in question, I jumped in and had a look.

I think I'm on the right track. Port 15 is on VLAN 99 which is my guest network, and it's currently not connected which makes sense because the BluRay player is turned off. The next step is to be 100% sure this is the BluRay player. I run down to the room that has the player in it and turn it on...

BOOM! ok, so this is clearly the BluRay is on that port. It auto detected the speed/duplex at 100/full, but with errors all over the place in the logs. So I changed the port to half duplex (leaving the speed auto).

and now the port looks like this.

I fired up Netflix on the BluRay and it loaded faster then I've ever seen it.

Super cool. So what network monitor am I using? As pictured in the beginning of this article, I downloaded a pre-configred appliance build of a product called Observium. I guess it's fairly popular, but I'd never heard of it.



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