Need Help in Nat Scenario!

nagare_sainath · ‎04-14-2015

Hi Experts,

I am facing issue in NATing.

We are planning to move Old server (physical) to new Server (Virtual). We have two different subnet for Physical (172.24.1.0/24) and virtual (172.24.7.0/24).

However issue is this server application has a client installed in every USER's machine with OLD Physical server IP manually configured in it.

Now if I am moving it to the vritual I have to change and assign the server IP from Virtual server ip range thus same has to reconfigure manually on the User client which is more hectic as I have more than 2000 users.

So I have thought of destination nating it on my core switch as I don't want to configure the server ip on each user client on each machine. (if is there any other simple technique available please let me know) .

I have attached image of my scenario with packet structure what I want.

Could you please help me with the configuration in my scenario and on which interface should I apply the same ?

User LAN Subnet (172.24.0.0/16)
NEW Server Subnet (172.24.7.0/24)
OLD Server Subnet (172.24.1.0/24)

Core Switch loopback is 172.24.0.1

P.S: Please let me know if I am missing any other technique available instead of Nating.

Thanks,

SAINATH

Nithyanandan P · ‎04-16-2015

I strongly recommend that use hostname for accessing servers because whenever like this situation, you just need to modify entry in the DNS server that hostname === > Point to New IP.

Also in the future if you look for server high availability and performance etc., you may do Load balancing traffics through load balancer device. so it just a matter of modifying FQDN (DNS Entry).

so it is a best solution as per my view.

you can try NAT option and need to apply in SVI interfaces. Instead of applying NAT for all the IP's, just test with few IP's (By using ACL) and test it. I never tried NAT between two SVI's and look for your updates.

Ruben Cocheno · ‎04-17-2015

I would keep the same IP on virtual server even on a subnet of physical servers, they are just servers.

DNS is always welcome, keep headaches away :)

Assuming the application traffic is NAT(able) can be a solution, but probably you will loose performance on your L3 device (even crash) and you will have other issues (application performance) to solve

Tag me to follow up.
Please mark it as Helpful and/or Solution Accepted if that is the case. Thanks for making Engineering easy again.
Connect with me for more on Linkedin https://www.linkedin.com/in/rubencocheno/