Failing virtual interface, please help

I'm using RedHat 9.0 and have setup iptables as a firewall/nat. On this
particular server, there are two virtual interfaces in addition to the main
WAN IP. On one of the IPs, I'm forwarding port 80 to an internal address.
I'm having a very strange symptom. It will work for a little while and then
when you try to hit this IIS 5.0 website (which uses NTLM authentication),
it fails...you just get the white screen in your browser. If I issue an
'ifdown eth0:2' and then 'ifup eth0:2', the website starts working again for
a while but eventually it happens again.

Here is the setting for the virtual interface:

DEVICE=eth0:2
BOOTPROTO=static
IPADDR=63.xx.xx.xx
NETMASK=255.255.255.252
ONBOOT=yes

Here is part of the iptables script:

iptables -A PREROUTING -t nat -p tcp -d $ext_if2 --dport 80 -j DNAT --to
192.168.168.117:80

The funny thing is that I'm also forwarding port 23 via a different virtual
interface to a different internal server, and it never seems to fail.

Does anybody have any suggestions for this issue?

Thanks,
Marv

Figured it out. Client gave me the wrong subnet mask or something. It ends
up that the virtual interface in question is configured with the broadcast
address. It works for a while, and then I guess it disables itself.

Funny, that his NetScreen firewall was working with the configuration?

"Marv" <marv@somewhere.com> wrote in message
news:Pt40c.52599$k51.38835@newssvr33.news.prodigy. com...
> I'm using RedHat 9.0 and have setup iptables as a firewall/nat. On this
> particular server, there are two virtual interfaces in addition to the
main
> WAN IP. On one of the IPs, I'm forwarding port 80 to an internal address.
> I'm having a very strange symptom. It will work for a little while and
then
> when you try to hit this IIS 5.0 website (which uses NTLM authentication),
> it fails...you just get the white screen in your browser. If I issue an
> 'ifdown eth0:2' and then 'ifup eth0:2', the website starts working again
for
> a while but eventually it happens again.
>
> Here is the setting for the virtual interface:
>
> DEVICE=eth0:2
> BOOTPROTO=static
> IPADDR=63.xx.xx.xx
> NETMASK=255.255.255.252
> ONBOOT=yes
>
> Here is part of the iptables script:
>
> iptables -A PREROUTING -t nat -p tcp -d $ext_if2 --dport 80 -j DNAT --to
> 192.168.168.117:80
>
> The funny thing is that I'm also forwarding port 23 via a different
virtual
> interface to a different internal server, and it never seems to fail.
>
> Does anybody have any suggestions for this issue?
>
> Thanks,
> Marv
>
>