How to check for network congestion 1

[dandan123]

Today we had a problem where our entire network slowed down.

It turned out that backups had not completed and once they were killed things returned to normal.

As a Unix admin what tools are available to check for network congestion ?

 

[AnotherAlan]

Hi dandan,

I would suggest using the switches with netstat.
For example, netstat -i will show inboudn and outbound packets including any colisions.

I'm not too hot on the network side of things, but netstat usually tells me what I need.

Hope this helps

 

[spamly]

Try iftop

It's available on sunfreeware.com

 

[mmumdzie]

Hi,

I had to investigate the same issue some time ago. Thank God for Ethereal. You can download it on Solaris freeware site. Fabolous tool. I installed it on Solaris 8 machine and exported display on my laptop. Of course you have to use some X terminal in order to obtain GUI. I used hummingbird exceed. You get graphs where you can read just everything. I was analysing special commands that we send via network and congestion that they are using. Do not look any further -> Ethereal.

 

[dandan123]

mmumdzie,

Would you know if ethereal loads the network in any way ?

 

[mmumdzie]

No it does not. It simply monitors the Network interface of the host machine. You can eavesdrop the Network without influencing it.

 

[coffeysm]

You can try using nttcp or something similar. It will setup a connection between two machines and then tell you the statistics. As far as network congestion you might need a fluke or something.

 

[hcclnoodles]

ntop is a great tool, when the ntop process starts it starts its own webserver which you can browse too to get graphs etc of current network activity ......i couldnt live without it