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New Member

How to define back connection persistence

Hi All,

I have a router which receives connections from the different machines but with the same IP (Balancing). I would like to know how, if its possible, to configure Cisco router to reply to the same machine where from the last connection is received, I assume it should be done according to a MAC address mapping.

Machine1 (mac=x, src_IP=A) ---- R ---- WEB Server

Machine2 (mac=y, src_IP=A)-----/

If last connection with the source A is received from machine1, the reply should be sent towards the same machine.

thanx !


Re: How to define back connection persistence


Kindly let us know whether you are using the IOS SLB feature in your Router.

There is a configuration option available while configuring SLB feature, by which you can ensure that the connection from the same client to the Virtual Server will be tied to the same physical server.

For more clarity, kindly go through this URL.

However in your example i could see that you have mentioned one webserver and two clients with the same ip address. Is this the real scenario that you are trying to test.?

I wonder whether it will be possible in real scenario's with client system having the same ip.

IOS SLB is a feature that you can use to create server farms for same purpose, with many physical machines all having a same virtual ip. Clients trying to access the services will attempt to access the same via the virtual ip. The IOS SLB software will interpret these client requests to virutal IP and handle them properly to distribute it to different physical server. For the client the whole process will be transparent.

Can you clarify more and Let us know whether the IOS SLB feature is is applicable to your scenario.

Hope this helps.


New Member

Re: How to define back connection persistence

Hi !

thanx for reply!

Sorry for confusing you a bit, but the whole scenario looks as follows:

Client(IP=A) --- Internet ---- FW1-----R-- Web


Basically, the client with the static IP=A is trying to connect to a Web server allocated behind two Firewalls (FW). The Web server is attached to an internal router (R) which leads to the Internet via two FWs.

The Client can connect either via FW1 or FW2 and get to the Web server, however the FWs do not perform any source NAT, therefore the src IP of the client is preserved.

My internal Router should provide sticky decision on connection and reply back to the same FW where from the last connection has been opened.

I have found something like this:

But it requires some modules, I am running on a regular router 3000 series.

Do I have the same capabilities to allow sticky decision on the regular or specific IOS without using an additional modules?

thanx in advance.