CS?AIX supports NAT?

[NIck Dakoronias]

Hello CommServer forum readers,
Any advise on the following will be much appreciated:
There is a project coming where CS/AIX -acting as TN3270 servers (TCP
session requests)
planned to be deployed on Production and Disaster Environment with identical
configuration
including same IP adresses and host names for disaster recovery purposes.
The idea is to use the same IP/host names (same network subnet) at both
sites (Prod/Disaster) and make transparent
the transition for application users, using NAT translation (routing)?
Is this theortically correct and technically feasible?
Any other alternative?
(How about using DNS resolving different host/IP adresses from both sites to
the same virtual address?)

Any advise will be much appreciated.

Regards
Nick Dakoronias (ITS/Athens)

[l***@us.ibm.com]

Post by NIck Dakoronias
Hello CommServer forum readers,
There is a project coming where CS/AIX -acting as TN3270 servers (TCP
session requests)
planned to be deployed on Production and Disaster Environment with identical
configuration
including same IP adresses and host names for disaster recovery purposes.
The idea is to use the same IP/host names (same network subnet) at both
sites (Prod/Disaster) and make transparent
the transition for application users, using NAT translation (routing)?
Is this theortically correct and technically feasible?

Yes.

The NAT function is outside of CS/AIX.
CS/AIX does not know or care that the incoming
session was NATted before it reached AIX.
I don't think that even the AIX tcp/ip stack
would know or care and if the AIX tcp/ip stack
doesn't know then CS/AIX (one layer higher)
would not know.

Post by NIck Dakoronias
Any other alternative?
(How about using DNS resolving different host/IP adresses from both sites to
the same virtual address?)

See my response to your previous post which
described this scenario. I don't know of an
IBM DNS product which does this, but I know
there are non-IBM DNS add-ons which do it.

Since AIX has some very nice VIPA support, you can
have each of the AIX server have both a unique
native tcp/ip address and a shared/common VIPA address.
Then use the unique address to manage/install/monitor
each server individually and use the VIPA address as
the target in the client's config.

Paul Landay

[l***@us.ibm.com]

One thing to keep in mind is that CS/AIX will report
in the CV64 the address of the client that it sees,
not the address as seen by the NAT router.
More info on CV64 is at:
http://www.ibm.com/support/docview.wss?uid=swg21192649
http://www.ibm.com/support/docview.wss?uid=swg1IZ12727
In your case it shouldn't matter because it is the
tn3270 server's address which is being NATted, not
the client's address, but I post this here in case
someone in the future does NAT of the client and
find this post with this Subject:

Paul Landay