Re: Adding a 2nd NIC
Michael Boyd wrote:
>
> Hello all,
>
> A week or two ago I raised a few queries regarding the addition of a
> second NIC to my firewall to create a DMZ for a web server. I will
> continue to use dial-up access to the internet for the time being via
> ppp0. The eth0 interface is to be protected by a strong ruleset with
> eth1 being the DMZ.
>
> I have added a second 3c509 to my machine which is identified on boot
> and labelled eth1. I can't seem to assign eth1 an IP address whether I
> edit config files or use ifconfig. I get a message saying...
>
> SIOCSIFFLAGS:Resource Temporarily Unavailable
>
> I found numerous references to this problem using google but can't
> follow the first suggestion, ie turn off PnP in the BIOS, as it is an
> old 486 and doesn't have this option.
>
> To try and find out which card is eth0 and which is eth1 I have a
> network cable plugged into each card and my hub. I can ping the
> firewall (Alpha) from my windows machine (Beta). I can also ping Beta
> from Alpha but get the following:-
>
> PING Beta (192.168.1.3): 56 data bytes
> 64 bytes from 192.168.1.3: icmp_seq=0 ttl=128 time=3.3 ms
> 64 bytes from 192.168.1.3: icmp_seq=1 ttl=128 time=1.8 ms
> 64 bytes from 192.168.1.3: icmp_seq=1 ttl=128 time=2.5 ms (DUP!)
> 64 bytes from 192.168.1.3: icmp_seq=2 ttl=128 time=1.6 ms
> 64 bytes from 192.168.1.3: icmp_seq=2 ttl=128 time=2.3 ms (DUP!)
>
> It looks to me as though it is using both interfaces to do the ping.
> Which strikes me as being odd as the second one doesn't have an IP
> address assigned to it. The collision LED on the hub goes mad too.
>
> If I remove either of the network cables and try to ping Beta the
> machine goes into an infinite loop which needs a power cycle to clear.
>
> I am reluctant to admit defeat but am on the verge of removing the 2nd
> NIC.
>
> Can anyone help resolve this? I read about a DOS utility called
> 3c5x9cfg that can be used to change IRQs. Is that what I need? If so,
> can I use it even though the Alpha box only has Debian on it?
>
It looks to me like you have the two nics configured to use the same
address for io and the same interrupt. The answer should be to use
3c5x9cfg to reconfigure one of the cards, you can probably find a
working 3c5x9cfg for linux if you try with google.
Make sure to physically remove one of the nics before reconfiguring
the other or you might accidentally reconfigure both of them.
Happy hacking,
\Gandalf
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