IP_Forwarding

[Derrik Pates]

On Fri, 29 Jun 2001, Shin Neng Wong wrote:

> I have a server with 2 NICs.  Before testing out my firewall script, I just ran
> a test.  the server is configured with an external NIC (203.121.12.69) and
> internal NIC (10.10.10.1).  IP forwarding is disabled i.e cat
> /proc/sys/net/ipv4/ip_forward produce 0.  An internal host (10.10.10.2) pinging
> my server's external IP (203.121.12.69) actually works.  How come?  Am I missing
> something here again?  *looking confused*

This is not unusual. I don't know why Linux does this, but you still
should not be able to ping anything else on the external net that way (or
send any other packets in that fashion through the box in question).  If
you can do _that_ then you definitely have some kind of bug on your
hands...

Derrik Pates      |   Sysadmin, Douglas School   |    #linuxOS on EFnet
dpates@dsdk12.net |     District (dsdk12.net)    |    #linuxOS on OPN