slow networking when add default route

[Rick Garland]

Hi all:

Got a RH Linux AS 2.1 system on a Dell Poweredge.

The system is in the DMZ with another RH Linux system. I can talk between systems w/o the default route. But their are certain services than need it, i.e., ntp. So I added the default route to the systems.

When I add the default route to the systems, the network reponse times to the systems becomes painfully slow. What is happening?

[Steven E. Protter]

check the ping times on those routes before adding the default route.

See if they are consistent.

Also, try traceroute and see if there is hangup between you and the route destination.

If so, contact network administration.

I've had similar problems that had nothing to do with default routes.

I had inconsistent and conflicting data in these files..

/etc/sysconfig/network-scripts

the ifcfg-eth0,ifcfg-eth0:1 etc.

If you are running multiple interfaces like I do to run my web hosting business, consistency issues there can really slow you down.

Does the gnome or kde environment run very slow on the console when this symptom shows itself. Its a sign of network issues.

take a look at the files, make sure everything in there is right and consistent(netrwork address, subnet mask).

then

service network restart

I'd also make sure the addresses on the two interface cards(if the machine is acting as a router) aren't the same subnet or anything like that. Again inconsistencies can lead to performance problems.

Lastly, does sendmail start very slow. Its anohter pointer to the issues I describe above.

netstat -an

netstat -rn

if it works netstat -I eth# 3

replace pound with the number of the nic interface.

if that last command, stolen from HP-UX works it will give you a packet/network traffic snapshot every three seconds with summary tables every minute or so. Slow number here point to network configuration issues.



good luck

SEP

[Rick Garland]

Done a lot of checking as stated above - but there are no inconsistencies. Each system has 1 NIC card being used and that is all that is configured and plugged in - just 1 NIC.

Things appear to be OK yet it is very slow in doing various commands such as route, netstat -nr, ntpq -p, etc...

[Steven E. Protter]

Any errors in the system logs?

If seems to be your box, but the whole thing is suspicious.

I use a Poweredge for my web hosting business, and have overcome such issues.

If your NIC is a buildin, have you checked for current drivers?

I'm going to look through my Linux Admin book tonight and post anything that seems familiar.

You might want to cruise the red hat forums and see what you find there. More users. I bet Stuart Brown, Cheif guru might think of something when he comes online in Australia later tonight(morning there).

SEP

[Rick Garland]

Found it.

These systems are in the DMZ and I haven't placed a system in the DMZ for some time now.

My typical installs include setting up the DNS info on the systems as well so I configured the resolv.conf file - not think (at that time) that it would have trouble looking back through the DMZ to the network.

Ahhh... what wonders a bottle of rot gut will do, it clears the mind ...

Many thanks!