Am So, den 14.11.2004 schrieb Bill Somerville um 22:11:
I have pppd set to dial on demand on my router and find it occasionally wakes and dials when I use ssh to connect to a node on my local sub-net. I've tried setting up an iptables LOG rule for any outgoing traffic on the ppp device but nothing gets logged when it happens. Does anyone know what sort of packet causes this? It only seems to happen when ssh hasn't been used for a few hours so I'm guessing it's something to do with nameserver caching but can't work out what.
Bill Somerville
Yes, in most cases like yours it is a name resolving issue. You didn't tell whether you run a local named or other details about your setup. Other that an iptables log rule for port 53 UDP/TCP I would suggest using tcpdump to find the cause for the DoD.
Thanks for that. Got to the bottom of this with logging on nameserver. It appears that ssh tries IPv6 as well as IPv4 and the AAAA lookup is being forwarded by our local nameserver, hence the wake up of pppd.
I know that I can rebuild ssh so that it only tries IPv4. But is there an easy way of setting up the local nameserver so that it doesn't forward the AAAA lookup?
Alexander
Bill Somerville
