Re[2]: [despammed] Re: odd networking problem
Monday, October 7, 2002, 3:48:39 PM, Stephen Gran (Stephen) wrote:
Stephen> 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 ;)
Stephen> Firewall on the box in question? Sounds like something is rate-limiting
Stephen> the pings, and if the box just stops sending them, it's probably the box
Stephen> itself, rather than anything past it.
No firewall. I thought at first it would be something like.. ugh, I
forgot the name *again*. Anyway, some congestion protocol in 2.4,
however it wasn't enabled.
Stephen> Other things to try (missed the beginning of this thread):
Stephen> Look at route -n - do you have more than one gateway?
Checked that out. I thought it might be learning some weird route or
something. No dice. :(
Stephen> tcpdump/etheral on the box in question at the same time as on the router
Stephen> - is the box sending packets that the router never sees?
I didn't try that. I'm going to try that now.
Stephen> pinging hosts on the internal network - does this work OK? If so, maybe
Stephen> it really is firewalling on the router.
Yes, pinging local hosts is fine. I'm going to turn off the firewall
on the router and just put up a ipchains -A forward -j masq, just to
see if it works then.
I am also going to try doing a hard reboot as Jeff said, I havn't
tried that. Thank you both for the help so far, I will let you know
if anything works ;)
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