[lug] Very long network connection times?

[Alan Robertson]

"Scott A. Herod" wrote:
> 
> Hello,
> 
>   A question about networking, probably tcpd in particular.  I have
> two nearly identical PIIs running RH 6.2 at home that are connected with
> ethernet.
> One has a linksys card ( BTW, I noticed that the latest tulip driver
> will not compile with the headers from 2.4.0 test 7; netdevice.h has
> changed ) and the other a 3Com card.  The two machines have IP addresses
> in 192.0.2.*, the netmask on each is 255.255.255.0, the gateway on
> each is set to 192.0.2.254.
> 
>   They live on an isolated network ( the ultimate firewall ) so I
> have no actual machine acting as 192.0.2.254.  Neither is
> supposed to use DNS according to linuxconf, they are in each
> other's /etc/hosts file.  Neither machine has routing enabled.
> 
>   However, when I telnet from the 3Com machine to the linksys machine
> I get an immediate response.  When I telnet from the linksys machine
> to the 3Com machine it takes about 2 minutes before the prompt
> actually appears.  ( rlogin and ftp are similar. )  Even if I do
> "ftp localhost" on the 3Com machine, it takes about 2 minutes for
> a prompt to show up.
> 
>   Can anyone suggest where else to look for a problem?  Does linuxconf
> lie about the DNS look-up?  I use the 3Com machine for dial-up access
> and had it using DNS so that that would work, but told linuxconf to
> turn off DNS while I was trying to fix my internal network slowness.
> 
>   If the issue is tcpd trying to do name verification, why would one
> machine be different from the other?

TCP wrappers do look up names.  You might try putting it in /etc/hosts and
see if that helps you diagnose the problem.

Another possibility might be that it was trying to get ident information.

	-- Alan Robertson
	   alanr at suse.com