Re: [TCLUG:15059] Strange routing problem

[Nate Carlson <natecars@real-time.com>]

On Wed, 22 Mar 2000, McNitt, Jennifer wrote:

> All of a sudden (happened sometime late last week), routing in my home's lan
> has seemed to have stopped working.  I have no clue why it is not working or
> what happened to stop it since I haven't touched my Linux box in a long
> time.
> 
> My current setup is (the names of the boxes are in ()'s):
> 
> Dedicated 56K modem line
> (spot) 486 box running Red Hat 6.2 - 1 lan card - 1 modem card connected to
> ISP - acting as a router and that is about it - IP forwarding turned on -
> has own IP - running a DNS server too
> (bbs) Pentium 166 box - NT Server - 1 lan card - Running FTP, HTTP, mail
> server - points to spot as its gateway - has own IP
> (kerowyn) Pentium 450 box - 1 lan card - My "play" workstation running Win
> 98 - points to spot as its gateway - has own IP
> 
> "Spot" dials out to my ISP and starts the connection.
> 
> When logged into "spot" I'm able to ping external Internet sites such as
> www.yahoo.com and www.cnet.com.  I'm able to ping "bbs" and "kerowyn" too.
> 
> When logged into "bbs" I am not able to ping external Internet sites.  I
> receive a timeout error.  I'm able to ping "spot" and "kerowyn" only if I
> have their IP numbers defined in my hosts file.
> 
> When logged into "kerowyn", I don't have a hosts file setup.  I am only able
> to ping "spot" and "kerowyn" if I have "spot" listed as my DNS server.
> 
> I'm unable to ping my ISP's DNS servers from "bbs" and "kerowyn".  I can
> ping the DNS servers from "spot".
> 
> This seems like some time of routing issue but I sure can't find the
> problem.  I have powered down all of the machines and rebooted them.  Routed
> is runniing when I check the processes on "spot".  When I type "route" on
> "spot" the routing list looks the same as it did when things were working.
> 
> Any ideas on things I could check on?
> 
> Thanks,
> 
> Jen McNitt
> 

cat /proc/sys/net/ipv4/ip_forward and make sure you get a '1' returned?
make sure ipchains is accepting forwarded packets?

-- 
Nate Carlson <natecars@real-time.com>   | Phone : (612)943-8700
http://www.real-time.com                | Fax   : (612)943-8500