Is your setup such that outbound packets are sent via the PPP (serial
port) link and inbound packets are received on the cable modem? If so, you
need to patch the NAT code in the kernel. Let me know what version of
NetBSD you're running and I'll send you a patch.

scott

On Thu, 22 Oct 1998, James Snow wrote:

> 
> Thanks to everyone who helped me with my com port/modem problem. I've
> subsequently set up PPP without a hitch, but following the directions for
> NAT has got me stumped.
> 
> I've got ipfilter compiled into the kernel., and I have it enabled in
> /etc/rc.conf. I have an empty /etc/ipf.conf, the following in
> /etc/netstart.local:
> 
>    if [ -f /etc/ipnat.conf ]; then
>                   echo 'starting IP network address translation (ipnat)...';
>                   /usr/sbin/ipnat -f /etc/ipnat.conf
>         fi
> 
> and the following in /etc/ipnat.conf:
> 
> map ppp0 10.0.0.0/24 -> 0/32 portmap tcp/udp 40000:60000
> map ppp0 10.0.0.0/24 -> 0/32
> 
> I'm a little confused about those numbers following the portmap command.
> Do they represent the range of ports that the machine will resend NATed
> packets from or the range of ports that a packet to be NATed must be
> coming from?
> 
> Back to the NAT problem though, with the above setup and one of the other
> machines here set to use the NetBSD box as its gateway, nothing happens.
> The output of ipnat -ls remains as follows:
> 
> mapped  in      0       out     0
> added   0       expired 0
> inuse   0
> rules   2
> List of active MAP/Redirect filters:
> map ppp0 10.0.0.0/24  -> 0.0.0.0/32  portmap tcp/udp 40000:60000
> map ppp0 10.0.0.0/24  -> 0.0.0.0/32 
> 
> List of active sessions:
> 
> I can verify with tcpdump that the client machine is indeed making
> requests and they are making it to the gateway, but the NAT doesn't seem
> to see tem at all.
> 
> Anyone have any ideas?
> 
> 
> Thanks in advance,
> James Snow