[AusNOG] Strange ADSL problem - troubleshooting / diagnosis advice wanted

[Ross Wheeler]

> I'm 99.99% percent it isn't coming from me or even to me directly, I 
> thought the same as you and did a lot of digging to double check.
>
> I have both SNMP and Netflow monitoring and logging configured on the 
> modem and neither show any significant activity during these time 
> periods on either the up or the downstream.

Recently encountered a problem for an associate, not entirely unlike your 
symptoms. When it was finally identified, his colo provider had a 
compromised host in an adjacent rack, but which was connected to the same 
switch as him. The compromised host was generating so much traffic the 
switch was being saturated, he was seeing higher response times, packet 
loss, at times loss of routes and all manner of perculiar things.

The traffic wasn't visible to his host(s) or on his network.

(I know that doesn't involve DSL!)

R.