Ping time strangeness

[vodkaman]

Hi Everyone,

One one of our clients networks we're having an internet connectivity issue that appears to be an issue with the ISP - occasionally the connection get's very slow.

The ISP (AT&T) checked the lines and did their troubleshooting and according to them everything is perfect. They are blaming our internal network for the problem.

A ping test to the firewall is perfect.

One thing thats strange is that if I log into one of their machines via VNC and run a continuous ping to google - it looks so so, but when I take the ping window and move it around (stressing the connection just slightly) the ping time goes crazy! I tested this on other client machines without the same result. Browsing the web creates the same issue.

Seems like you put any strain on the connection and ping slows way down.

Any thoughts about what this might be?

 

[cajuntank]

What you'll have to do to get AT&T to help out more is disconnect your network from their DSL modem (assuming you have DSL) and connect the modem to a single computer (make sure it's virus free) to do tests with. Do continuous pings to various addresses to get a better benchmark on the connectivity. Also perform some traceroutes to see if things are timing out more that they should on the way. If this is a T1 circuit or better, then AT&T should have helped you out better troubleshooting this. Call the NOC again and try someone else (again if this is a T1 or better circuit).

 

[vodkaman]

Thanks for the fast response cajunktank.

It's only DSL - but AT&T has been pretty good about helping - they can only read the BS from the script which doesn't really do much to address difficult problems.

They "checked their lines" and it turned out OK. We're going to connect it to a laptop directly and test again when we can (they are a retail business so it's difficult to just unplug their internet).

If anyone has seen anything like this let me know - thanks!

 

[jugghedd]

If moving the ping window around "stresses the connection", something is not right. That should have no bearing on the ping results on a normal PC/server. I'd say you have some kind of problem on that machine.

 

[vodkaman]

Hi Jugghedd,

I'm logged into the machine remotely via VNC so moving the ping window around is causing the screen to refresh - which would have a strain on bandwith (normally pretty much to the point of not affecting a ping test).

If anyone has any other thoughts let me know