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NAT Two External Addresses to One Internal Address

Is it possible to NAT two external addresses to one internal address?

If it is possible, is it good practice to do so?

If it is not good practice to do so, can you point me to documentation explaining why it is not good practice?

I have a consultant on site helping with a project. We currently have a static one-to-one NAT translation for our existing server. As part of the new project testing, the consultant is suggesting that we need another external IP address mapped to the existing internal server.

If it's not possible or not a good idea, I'll look into alternatives. I just want to have some supporting documentation if I have to tell him we can't/shouldn't do it.

Reply to
SCAdmin
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Meanwhile, at the comp.dcom.sys.cisco Job Justification Hearings, SCAdmin chose the tried and tested strategy of:

Should be. One possible reason for this would be if you had two broadband connections into one router, you could NAT both back to one server [say, an email server] for resilience.

Reply to
alexd

I have been pondering this and could not figure out if the router would accept it.

Turns out it does - seems quite reasonable to me.

ip nat inside source static udp 10.1.3.139 328 1.1.1.1 328 extendable ip nat inside source static udp 10.1.3.139 328 1.1.1.2 328 extendable

Weirdly - it seems to me - I did not type the mysterious extendable so it must be the default.

router(config)#$static udp 10.8.37.139 64328 1.1.1.1 64328

router(config)#$de source static udp 10.8.37.139 64328 1.1.1.2 64328

So yes, seems like a decent plan if you need some workaround or migration process. IDEAL!

Clearly, possibly confusing as a long term solution, however NAT is intrinsically confusing so a little more confusion probably won't hurt too much:)

Have fun.

Reply to
bod43

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