* Stateful port redirection?
@ 2010-03-03 22:48 Faré
2010-03-03 23:32 ` Pascal Hambourg
0 siblings, 1 reply; 2+ messages in thread
From: Faré @ 2010-03-03 22:48 UTC (permalink / raw)
To: netfilter
Dear netfilter hackers,
I'm studying options for Hot Upgrade for servers that require high availability.
Is it possible using netfilter to
a- redirect TCP traffic from port 10000 (visible to the public) to
port 10010 (invisible to the public)
b- change the rule so that that traffic to port 10000 is now
redirected to port 10020 (also invisible to the public) *except* for
packets associated with existing connections, that will remain
redirected to port 10010.
I can imagine that others have needed this feature and that it already
exists. Or I can imagine that nobody bothered about the connections
that were lost. I can also imagine heavyweight ways to do everything
in user-space, with the old server passing the TCP socket fd to the
new server over a AF_UNIX socket.
So -- has it been done before? If not, how hard would it be to add a
packet filter that would do that -- and that could be updated
dynamically to switch again to another port, etc.?
--#f
"I object to doing things that computers can do."
— Olin Shivers
^ permalink raw reply [flat|nested] 2+ messages in thread
* Re: Stateful port redirection?
2010-03-03 22:48 Stateful port redirection? Faré
@ 2010-03-03 23:32 ` Pascal Hambourg
0 siblings, 0 replies; 2+ messages in thread
From: Pascal Hambourg @ 2010-03-03 23:32 UTC (permalink / raw)
To: netfilter
Hello,
Faré a écrit :
>
> Is it possible using netfilter to
> a- redirect TCP traffic from port 10000 (visible to the public) to
> port 10010 (invisible to the public)
What do you mean by invisible ?
> b- change the rule so that that traffic to port 10000 is now
> redirected to port 10020 (also invisible to the public) *except* for
> packets associated with existing connections, that will remain
> redirected to port 10010.
Yes. This is the way stateful NAT works. Changes in NAT rules apply only
to new connections.
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2010-03-03 22:48 Stateful port redirection? Faré
2010-03-03 23:32 ` Pascal Hambourg
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