Re: IP Confusion

From: David Pollard (headly81_at_hotmail.com)
Date: 12/02/03 

Date: 2 Dec 2003 03:38:01 -0800

Hi Steve,
It sounds like a routing issue to me. It is looking out the wrong
interface for the destination address. This might be causing your
timeout problems also. DNS is another big thing for timeouts. If DNS
can't resolve something it trys for a while then gives up and does a
broadcast and either find it if it is on a local LAN segment or fails.

Not knowing the layout of you LAN makes it hard to sugest solutions
but I'd start off with only one ip on each nic and add more once you
get it working.

You probably need to add a static route that describes what can be
found through each interface. Don't forget you only get to have one
default gateway which is where it looks if no other route matches.

Check out the route command. The help for it is ok. Once you get it
right you will probably want to make the route persistant so it will
stick after a reboot.

Don't forget that the machine you are pining also needs to know the
route back through your linux machine to the network on the other
side.

I hope this at leasts gives you a direction to head in.

David.

Steve Robbins <srobbins@no.spam.charter.net> wrote in message news:<slrnbsn2u6.d9p.srobbins@robbinsga.charter.net>...
> I suspect I am missing something obvious, but I have a NIC that was
> responsive and now isn't.
>
> I am running RedHat 9 - SMP on a Dell PowerEdge server with two NICs.
> This server was replacing an existing server so I first took NIC 1 and
> hooked it up to a switch y.y.y.249 and set it up for DHCP (eth0). I
> configured NIC 2 for a dual IP Address (eth1, eth1:1), x.x.x.2 and
> x.x.x.3 and hooked it to a different switch but left these IP's disabled
> while I configured the system.
>
> All software tested out well (primarily PostFix and Apache were talking
> with other systems). I then disconnected the old server and activated
> NIC 2 on this system.
>
> Where it stands now and the problems: On NIC 2, x.x.x.2 is only for
> http traffic and it works fine. x.x.x.3 also works fine although
> telnet seems slow to respond as it takes about 10 seconds before I get
> anything back (and ssh will be replacing it once I get a port block
> lifted). I don't know if that might be an indication of something
> timing out before telnet reponds. NIC 1, which is set to DHCP is the
> problem.
>
> I get no reponse from it using anything (ping, telnet, http). Using
> traceroute, I get to its switch and that is it. If I am on the server
> and ping using the -I option so I make sure I am going out that NIC, I
> can ping my PC.
>
> I do have iptables turned off to make sure it isn't interfering.
>
> Any ideas are appreciated.
>
> Steve

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