20+ sec delay establishing a connection.

matt_d · 05-28-2006, 02:03 PM

Hello everyone,

Before I start here is my current network setup: I have a router that sits between the net and the lan. Obvously the router is the lan's gateway to the internet.

I have been working on this annoying problem for over 20 hours now! Ouch. Anyway, all of a sudden one of my linux boxes (FC4) would not resolv any domain names. It would not even connect to the gateway (which is acting as the dns server). I tried on five other computers, all worked just fine. I tried to ping the router as well as other systems on lan, but no traffic was going though.

While trying to figure out the problem, I would all of a sudden be able to ping other systems. And, it would finally resolve dns names, with a HUGE delay, about 20 seconds or so. Then, it would go right back not being able to see anything.

Now, it is back to resolving domain names and connecting with the outside world and lan. But there is still about a 20 second delay before it gets out anywhere. If I ping a lan address, it has a delay and if I ping an outside source it has a 20 second delay. There is a 20 second delay for any type of TCP traffic to any destination.

The network card in the box is brand new. I tried swapping in another one, but same results.

Any idea's why there is such a long delay? Can someone point me in the right direction to figure out what is wrong?

I did check the router and it is fine. All other systems connect to other lan systems and the outside world instantly.

Thanks,

-Matt

btmiller · 05-28-2006, 02:11 PM

Can you post the contents of /etc/resolv.conf and /etc/nsswitch.conf? Let's make sure the machine has the right DNS servers set up and is configured to use them.

Another useful tool is to strace the ping process so we can know exactly what it is hanging up on during that 20 seconds.

matt_d · 05-28-2006, 02:24 PM

Thanks for your repy:

the dns server in resolv.conf is correct ... ip 10.0.1.1

Here are the files:

Quote:

[resolv.conf]
nameserver 10.0.1.1

Quote:

[nsswitch.conf]
passwd: files
shadow: files
group: files

#hosts: db files nisplus nis dns
hosts: files dns

# Example - obey only what nisplus tells us...
#services: nisplus [NOTFOUND=return] files
#networks: nisplus [NOTFOUND=return] files
#protocols: nisplus [NOTFOUND=return] files
#rpc: nisplus [NOTFOUND=return] files
#ethers: nisplus [NOTFOUND=return] files
#netmasks: nisplus [NOTFOUND=return] files

bootparams: nisplus [NOTFOUND=return] files

ethers: files
netmasks: files
networks: files
protocols: files
rpc: files
services: files

netgroup: files

publickey: nisplus

automount: files
aliases: files nisplus

matt_d · 05-28-2006, 02:47 PM

Found the problem ...

My DNS server, for some reason, is only giving slow responses to his ONE box.. Weird.. I switched to my backup dns server and it sped everything up.

Thanks for everyones help!