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temporary host reroute?
I wonder if anyone can tell me whether the following is possible, and
if so, how? My knowlege of routing & subnets isn't far enough along
to know for sure myself:
I have two separate LANS in two different physical locations. Each
LAN is connected to the internet via a firewall that does IP
filtering/forwarding. In both cases the firewall is a Linux box that
I control, and the internal network is a subnet. There's a web server
inside subnet #1:
internet
... ...
/ \
/ \
/ \
--------- ---------
| fw #1 | | fw #2 |
--------- ---------
| |
| |
LAN #1 LAN #2
(subnet #1) (subnet #2)
including
web server
Suppose the web server's IP address is '1.2.3.4'. If the web server
goes down, I'd like to reprogram a machine inside LAN #2 to take on
IP address '1.2.3.4' and reprogram the firewalls to forward the
packets to the new location.
I know how to make a new machine take on an additional (or different)
IP address. What I don't know is how to set up the routes in the firewalls,
or even if it's possible. I don't have control of any of the routers
upstream from my firewalls, and normally they're configured to route
IP address '1.2.3.4' through fw #1. So I'd like to set up fw #1 to
route packets it receieve for 1.2.3.4 over to fw #2, which would then
send them on to the 'new' 1.2.3.4 in LAN #2.
I experimented with it unsuccessfully. I did manage to get a machine
inside LAN #2 to take on the IP address 1.2.3.4 (of course I used a
real IP address when I did it; I'm just using 1.2.3.4 in this message
as an example) and I got the routes on fw #2 set up so that fw #2
could ping 1.2.3.4. I then tried to set up a static host route on fw
#1 specifying fw #2 as the gateway for reaching 1.2.3.4, but this
didn't work. fw #2 couldn't ping 1.2.3.4.
Can someone tell me if this is possible, and provide some hints
on how to set up the routes?
Thanks in advance,
--Mark
Mark Phillips @ Geometry Technologies, Inc.
550 Gilbert Building, 413 Wacouta St., St. Paul, MN 55101
Phone: 651-223-2884 Fax: 651-292-0014
mbp@geomtech.com http://www.geomtech.com