It all makes sense now :)

As much of a kludge as it is, the individual NAT pools will be perfect. 
There's several offices, which means several IP addresses will be used if I
make individual pools.



-----Original Message-----
From: Doug S [mailto:[EMAIL PROTECTED]]
Sent: Friday, 10 January 2003 6:45 AM
To: [EMAIL PROTECTED]
Subject: RE: Load balancing & NAT [7:60663]


The way PAT works when overloading multiple addresses is to overload the
first address in the pool until ALL port numbers are used up.  I can't point
you to any publicly available documentation on this, but cut and pasted from
Network Academy curriculum:

"However, on a Cisco IOS router, NAT will
 overload the first address in the pool until
 it's maxed out, and then move on to the
 second address, and so on."

I've seen people wanting to get around this behavior for a variety of
reasons and I haven't seen anyone post a good reply.  I've come up with a  a
workaround that I beleive should work for you, although you'll have to take
a good look at your inside local addresses and figure out how to best define
those in to two equal groups.  Each group could then be separately
translated to a different address.

For instance, if you are now transating 8000 inside addresses all in the
range of 10.0.32.0/19 to one overloaded pool, you could configure it to
translate 10.0.32.0/20 to one overloaded pool and 10.0.48.0/20 to a separate
overloaded pool something like

#access-list 1 permit 10.0.32.0 0.0.15.255
#access-list 2 permit 10.0.48.0 0.0.15.255
#ip nat pool LOWER_ADDRESSES_TRANSLATE_TO 209.211.100.1 209.211.100.5 pre 24 
#ip nat pool HIGHER_ADDRESSES_TRANSLATE_TO 209.211.100.6 209.211.100.10 pre
24
#ip nat inside source list 1 pool LOWER_ADDRESSES_TRANSLATE_TO overload
#ip nat inside source list 2 pool HIGHER_ADDRESSES_TRANSLATE_TO overload

Forgive me if I've screwed up the syntax somewhere, but the idea is there. 
As I said, you'll have to put some thought into what best works in your
addressing scheme to best separate translated addresses in to two roughly
equal groups.  You might even find it helpful to partition them in to more
than two groups.

Hope it helps.




Message Posted at:
http://www.groupstudy.com/form/read.php?f=7&i=60766&t=60663
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