Subject: Re: nat on alpha
To: None <, port-alpha@NetBSD.ORG>
From: Ross Harvey <>
List: port-alpha
Date: 05/12/1998 11:08:04
> i know that nat doesnt work in 1.3 on alpha but does it work in 
> previous releases?  i have an alpha that would very much like to
> use as a gateway (that was why i really bought the thing) but
> since nat is broken in 1.3 im sorta stuck :(
> thanks
> nick

I spent a little time last weekend reading through the NAT code and I
can see a few places where it could be generating some 64-bit lossage.

Two people have reported that "NAT doesn't work".

Guys, that isn't a bug report I can do much with.

How about running netstat -p icmp, netstat -p ip, netstat -p udp, netstat
-p tcp, tcpdump, etc, and finding out where the packets are going? Are
they being dropped due to bad checksums, redirected away with botched
source or dest addresses? Do they come back out at all? Which protocols?
Do all ip packets die? What about icmp?

I've also asked for a loopback test, and both people said "huh?".
Well, one way to do that is to open /dev/tun0, fork off an ifconfig,
install NAT ops, and then send some test packets. This will duplicate
the problem with a single test program that requires no actual
network hardware, so I can run on both i386 (to see it work) and
alpha (to see it fail). You might even be able to do this with a
shell script, but certainly a small C program containing a few
system("...") calls should do. Otherwise, I probably have to set
up an 8 node network -- one 4 node network on i386 for the working
case and one 4 node network on alpha for the failing case...or
write this bug demo program myself.