[Date Prev][Date Next] [Thread Prev][Thread Next] [Date Index] [Thread Index]

Re: [despammed] Re: odd networking problem



This one time, at band camp, Ed McMan said:
> 
> 
> Monday, October 7, 2002, 12:39:40 PM, you wrote:
> 
> Jeff> Ed McMan, 2002-Oct-06 19:22 -0400:
> Jeff> <snip>
> >> 
> >> Here is the weird part.  This computer works fine using the same
> >> configuration in Windows.  All the other computers work fine too.  I
> >> have been trying to figure out what the problem is, so I did some
> >> packet sniffing with ethereal on the router.
> >> 
> >> I listened for any packets going to or from the debian machine in
> >> question.  I ran ping (some host on the internet) and let it sit.  The
> >> first two pings went through, and then it stopped.  The *really* weird
> >> part is that the machine stopped sending the pings!  Well, the router
> >> wasn't receiving them anyway.  Another oddity is that running
> >> /etc/init.d/networking restart on the workstation would fix the problem, for a few more
> >> packets.  After letting ping sit, another ping would go through about
> >> every five minutes.
> 
> Jeff> This is weird.  A few thoughts...
> 
> Jeff> - are there firewall rules on the router that might be limiting ICMP?
> no, the first few go through.  any other machine can also ping,
> traceroute fine.
> Jeff> - could system be on a bad switch port? or patch cable?
> nope, works fine in windows.
> Jeff> - are there errors being generated on the eth1 interface,
> Jeff>   e.g. ifconfig eth1 ?  perhaps a bad NIC?
> no errors, and it works in windows.
> 
> This is driving me nuts ;)

Firewall on the box in question?  Sounds like something is rate-limiting
the pings, and if the box just stops sending them, it's probably the box
itself, rather than anything past it.

Other things to try (missed the beginning of this thread):
Look at route -n - do you have more than one gateway?

tcpdump/etheral on the box in question at the same time as on the router
- is the box sending packets that the router never sees?

pinging hosts on the internal network - does this work OK?  If so, maybe
it really is firewalling on the router.

HTH,
Steve
-- 
Deflector shields just came on, Captain.

Attachment: pgpfCBUpEF1tV.pgp
Description: PGP signature


Reply to: