topic Re: Outbound connection through floating IP in Operating System - HP-UX

Outbound connection through floating IP

Pramod_4 — Mon, 04 Dec 2000 16:55:23 GMT

Hi,

I have a MCSG cluster with two nodes.
All incoming traffic comes to the system through the floating IP.

Is there any way to ensure that all outbound connections from the system ( where ever the package is running ) use the floating IP rather than the system IP.

Thanks in advance to all those who can reply.

Pramod

Re: Outbound connection through floating IP

Anthony deRito — Mon, 04 Dec 2000 18:28:26 GMT

Pramod, take a look at your routing tables. Run the command netstat -nr. Check out the "Interface" field. Each entry in your routing table will use the specified interface to route outbound traffic.

Tony

Re: Outbound connection through floating IP

John Palmer — Tue, 05 Dec 2000 10:56:48 GMT

Hi,

There is an interesting discussion about this at:-
http://docs.hp.com/hpux/onlinedocs/B3936-90026/B3936-90026.html

The section that is significant is the following:-

Call bind() before connect()

When an application initiates its own connection, it should first call bind(2), specifying the application IP address before calling connect(2). Otherwise the connect request will be sent using the stationary IP address of the system's outbound LAN interface rather than the desired relocatable application IP address. The client will receive this IP address from the accept(2) call, possibly confusing the client software and preventing it from working correctly.
-----------------------------------------------

Thus you must code your application to use the relocatable IP address if it is initiating connections.

If you are need to force 'standard applications' (such as ftp for instance) to use the relocatable address then it seems that your only option is to ensure that the relocatable address is the only address on that interface (also discussed at the above URL).

Regards,
John

Re: Outbound connection through floating IP

Dietmar Konermann — Tue, 05 Dec 2000 13:41:28 GMT

Hi, folks!

Generally, the application should be configurable to bind() itself to a specific relocatable IP-address instead of binding to INADDR_ANY.

Using 11.x You may use a static route to force outgoing traffic to be stamped with the 'right' source address...

# route add 0

You could add such a route during pkg start and remove during halt. But be careful, not to disturb heartbeat traffic using this trick!

Regards...
Dietmar.

Re: Outbound connection through floating IP

Pramod_4 — Thu, 07 Dec 2000 21:25:18 GMT

John:

It?s a running application, which uses many third part API?s and where we don?t have any control on it.