Re: [lvs-users] Weird problem with LVS-DR

To: " users mailing list." <lvs-users@xxxxxxxxxxxxxxxxxxxxxx>
Subject: Re: [lvs-users] Weird problem with LVS-DR
From: Joseph Mack NA3T <jmack@xxxxxxxx>
Date: Wed, 19 Dec 2007 10:04:26 -0800 (PST)
On Wed, 19 Dec 2007, Martijn Grendelman wrote:

> Since a while, directing traffic to the other machine (not the director)
> doesn't work anymore,

you don't remember changing anything I suppose? Any info 
there would go a long way to figuring out the problem.

> BUT ONLY on a specific VIP:PORT combination.
> During my tests, the LVS setup is as follows:
> martijn@whisky:~> rr ipvsadm -L -n
> IP Virtual Server version 1.2.1 (size=4096)
> Prot LocalAddress:Port Scheduler Flags
>  -> RemoteAddress:Port           Forward Weight ActiveConn InActConn
> TCP sh
>  ->            Route   500    0          0
> TCP sh
>  ->            Route   500    0          0
> TCP sh
>  ->            Route   500    0          0
> Note that all references to the local node have been temporarily
> removed.

removed on the machine (rather than removed from the 

> Now, the service defined second (port 81) works. The third one,
> port 80, but a different VIP, works too. The first one, the one that I
> need, does not.

the first and third VIP are both going to the same 
realserver. I take it that you have two VIPs on that 
realserver? I expect both the realserver and ipvsadm on the 
director should be able to handle this, but maybe not. If 
you delete the 3rd entry, can you now get to the service 
defined by the 1st entry?

I don't have great hope for this solution though.

> When I connect to, I see some kind of SYN storm on
> both the director and the real server on
> 14:37:42.232694 IP > S
> 557344343:557344343(0) win 5840 <mss 1460,sackOK,timestamp 218577173
> 0,nop,wscale 7>
> 14:37:42.232961 IP > S
> 557344343:557344343(0) win 5840 <mss 1460,sackOK,timestamp 218577923
> 0,nop,wscale 7>

don't see anything to/from the realserver here, but I don't 
know what it would tell me though. All packets from the 
realserver should go back to the internet, not to the 

Joseph Mack NA3T EME(B,D), FM05lw North Carolina
jmack (at) wm7d (dot) net - azimuthal equidistant map
generator at
Homepage It's GNU/Linux!

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