Reinstalling Networking on RH 7.2

[Guest_imported]

I installed RH 7.2 on a Linux Server to support Apache and other networking fuctions Telnet, FTP, Etc. I experience a lot of lag time when using any of these features. ie. web pages take longer than usual to load. Telnet sessions take 20-25 seconds to respond with a login: prompt. FTP times out altogether. I verified my host tables and order's and everything else based on a previous post to this group. I verified that my NIC card was working properly. I have two NIC's in this machine and the server acts the same way on either NIC.

I installed RH 7.2 from the same CD and loaded the same configuration on a different box, and it works fine. Telnet sessions immediately give a login: prompt. I experience no lags.

My question in the windows world if my TCP/IP stack becomes corrupted or I want to uninstall and reinstall particular aspects of networking I can do this. How and what would I need to do this in with Linux. I'm not as familiar with this environment. I think the networking component on the original server either loaded incorrectly or there is some type of corruption that would explain the behavior. I feel reasonably certain that I've addressed all the configuration issues.

Thanks,
Alain

 

[bgarlock]

Well, the tcp/ip stack is part of the kernel configuration. You could try rebuilding the kernel for your specific machine, but I doubt that is the problem. Generally, Redhat's Binary kernel's would be fine.

It sounds like your issue may be reverse DNS. What happens when you ping the IP of that machine? I would try adding the machines trying to telnet and ftp to that machine in it's /etc/hosts

Also, you should probably be using SSH instead of telnet, since passwords are sent in cleartext with telnet. Make sure you grab a recent SSH version, becuase there are security issues with older versions of SSH1.

 

[ifincham]

Hi,

Another thing to try would be to check the order in which the various name-resolution services are being checked, i.e. in /etc/nsswitch.conf . If you have an entry like :

hosts: nis files dns

and you are not using nis then I'd delete that to start with. Also, if you have unique entries in your /etc/hosts then put files first - e.g.

hosts : files dns

Restart the network and see if it makes a difference :

# /etc/rc.d/init.d/network restart

Hope this helps

 

[Guest_imported]

When I ping the machines IP I get a response.

nisswitch.conf is configured correctly.
hosts: files nisplus dns

I added the ip's of the host machines to the servers /etc/host table. The lag when I telnet has disapeared. So your reverse DNS theory could be right.

I don't understand why putting the telneting machines
ip in the host table would make things quicker. Isn't the IP address supplied to the server when you initiate the initial contact from the client machine?

 

[marsd]

That's not the way name resolution works.
If you want to disable name resolution use an -off(sic)
switch with a utility that supports it.
netcat -n -z 123.254.1.1 20-1024
ping -n 123.254.1.1
ad-nauseam.

 

[Guest_imported]

It also doesn't explain why I wouldn't have a problem telneting or network latency from a client to the server when there is nothing in the /etc/hosts table at all but I do to the original server.

 

[BlueAvatar]

try getting rid of NIS, i dont know if it will help, but i doubt you will be using it so its not going to hurt (much).