# Router needed with IP Aliasing



## InspectorGadget (May 14, 2005)

I need a little router with 100base-TX in and out, and a special requirement on the LAN side. It needs to alias 2 different IP addresses to its LAN NIC. It needs to serve a partial subnet of real IP addresses for a few servers that I have, but it also needs to serve an anonymous subnet with NAT.

In other words, I have several servers with real IP addresses and a real router LAN address, so I have to set the router's LAN address to that real address and have it provide standard routomg for that subnet.

But then I have several other computers (too many for my small set of real IP addresses) which need to browse the Internet. I have these set up on a standard anonymous subnet 192.168.1.xxx. I need the router to ALSO have 192.168.1.1 as its internal LAN address, and to provide NAT routing for this subnet.

I currently have a micro-BSD build booting from a floppy with routing and firewall functions configured to do the above requirements with "IP Aliasing" on the LAN-side NIC, but it runs on a regular PC which takes up too much space (not to mention power).

I would like to replace it with a small router box like all these cable/dsl routers you see at the stores. However, the vast majority of them only allow a single IP address for its LAN address. The only one that I've seen which allows aliasing additional LAN addresses is the ZyXEL "ZyWALL 2" (see the link below). What I don't know is if it will allow NAT on the anonymous subnet but standard routing on the hard IP. The only example they give is with several anonymous subnets (which all require NAT by definition).

ZyXEL ZyWALL-2 router link 

Anyone got an idea of what I can use (maybe cheaper than the $150 ZyXEL even if it would work), or should I stick with my micro-BSD box?

- The Inspector


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## johnwill (Sep 26, 2002)

I'd stick with what you have. I think the capability you seek will move you into the Cisco big buck territory. :smile:

You could always shrink the BSD system into a micro-ATX case with a KVM switch to another computer, it'll be almost as small as a router. :grin:


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