[defaultrouteuk]

Hi There - seems like a moving feast at this point. I still appreciate the feedback and the notes from john are great.

Sounds like you need a flat network with multiple subnets in it.

I'm thinking way off piste here and it's not something you'd do in the real world without a few beers first but you can have one broadcast domain (bridge/switch VLAN) and host more than one IP subnet. So you can have a static subnet of 192.168.11.0/24 for your FDDI hosts and either static of dynamic DHCP for your primary hosts (192.168.10.0/24). If you wanted everyone on the same subnet you could even make your linux router a bridge instead. I used to do that with ethernet and TR hosts (translation bridge I think we called it).

I could be missing your point but it feels like you need a simple way for your 25 (or more) SGI boxes to get online. We all know DHCP is designed for that. So I heard there are some issues with DHCP under IRIX but I can't imagine there will be so bad, it and bootp have been a standards for ages. So if DHCP is an issue just use BOOTP.

So yeah, if you need layer 2 communication and have one bridge then just have 192.168.11.0 and 192.168.10.0 in the same VLAN//bridge domain. Then cut and paste if you use static or dynamic addressing for each network card then adjust the host file to prioritise which network card you want to use for which purpose.

One other thing that came to mind is using source NAT on your linux router. If you setup a 1:1 NAT rule for 192.168.11.10 as like 192.168.10.11 or something then you can have everything on 192.168.10.0/24. Nodes in the 11 subnet will always address the 10 hosts and the hosts on the 10 network will address your 11 host as a 10.

Food for thought I hope at least.
Rich