Cisco 1721 redirect Public IP to different Public IP

I've been searching for days now and cant seem to find the answer to
this problem. Any answers, or pointers to places with the answer would
be greatly appreciated.

We have a fractional T1 with a block of 5 public addresses. 1 address
is being used with NAT for all network clients to access internet. 3
public address's/ports are being used to forward outside traffic to a
variety of internal servers/services. So far so good. Everything is
set up and running correctly.

Now ...we have a small remote office connected to internet via cable
modem/dlink router. The remote office holds mail/web server. The
remote office has one public ip assigned dynamically from ISP. I would
like to register website and mx records for remote office but due to
the nature of the dynamic ip assignment that is not feasible.

My idea: Register Remote office website and mx with remaining static
public IP at Main office. Then have cisco box at Main office redirect
all traffic for registered Public Ip to actual dynamic ip address of
remote office. I'll also have to come up with some kind of scripting
that changes that remote offices ip address on the cisco box
translation as needed, but I can cross that bridge when I get there.

What I need to know now is how to redirect all traffic bound for a
public ip on the cisco box to another public ip that is external to my
network.

THanks to all who apply,

Tony

 

:Now ...we have a small remote office connected to internet via cable
:modem/dlink router. The remote office holds mail/web server. The
:remote office has one public ip assigned dynamically from ISP. I would
:like to register website and mx records for remote office but due to
:the nature of the dynamic ip assignment that is not feasible.

Companies such as dyndns are set up to handle such matters automatically
and with a lot less grief than your redirection proposal.


:My idea: Register Remote office website and mx with remaining static
ublic IP at Main office. Then have cisco box at Main office redirect
:all traffic for registered Public Ip to actual dynamic ip address of
:remote office.

Have a static host route to a loopback interface that is marked
for ip nat, have the next hop from there be back out towards the
internet and have the other half of the nat configuration on the
outside interface. I'll leave it to you to work out which side
should be "inside" and which should be "outside".

 

Thank you Walter,

This is the first box I've ever configured so I will have to do some
research on on how to setup up the loopback interface correctly with
the nat configuration. I will respond with my success/or issues once
i have a configuration to test.

Tony