TCP-High Availability

Hi all!

I'm looking for solution to provide full redundancy on TCP layer. The
goal is to have two servers working in some kind of cluser, sharing same
IP address and able to continously operate TCP connections.
My idea is like the following: active, master server is responding to
TCP, sending ACK etc, and simultenously sending confirmations to slave
machine. If the master will crash, slave should switch to active state
and continue on same TCP connection.

Question: is there some ready solution ? I suspect, that some hacker
tool for "man in the middle" attacks should work in simmilar way, but i
didn't find anything interesting.
Additional question: is there any way to setup connection state in
linux TCP stack, so it will be able to continue connection ?

best regards
Jarek

Am Fri, 29 Jun 2007 15:14:10 +0200 schrieb Jarek:

> Hi all!
> Question: is there some ready solution ? I suspect, that some hacker
heartbeat, vrrpd,carp
or
http://www.google.com/search?q=linux+high+availability

Burkhard Ott wrote:
> Am Fri, 29 Jun 2007 15:14:10 +0200 schrieb Jarek:
>
>> Hi all!
>> Question: is there some ready solution ? I suspect, that some hacker
> heartbeat, vrrpd,carp
> or
> http://www.google.com/search?q=linux+high+availability

Unfortunetely, no one from suggested solutions is able to provide HA on
TCP level. If active server fails, all pending TCP connections will die.
I want to keep TCP connection open. The client shouldn't see that
something happend...

best regards
Jarek

Am Fri, 29 Jun 2007 16:29:10 +0200 schrieb Jarek:

> Unfortunetely, no one from suggested solutions is able to provide HA on
> TCP level. If active server fails, all pending TCP connections will die.
> I want to keep TCP connection open. The client shouldn't see that
> something happend...

Then vrrpd with syncd ist the right for you, place also a loadbalancer in
front of the server and nobody can see if one server fails.
(described on linux-ha.org)
cheers