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Re: ARP problems in 2.2.14

To: Suresh Rajagopalan <sraja@xxxxxxxxxxx>
Subject: Re: ARP problems in 2.2.14
Cc: lvs-users@xxxxxxxxxxxxxxxxxxxxxx
From: Julian Anastasov <uli@xxxxxxxxxxxxxxxxxxxxxx>
Date: Thu, 27 Apr 2000 08:09:21 +0300 (EEST)
        Hello,

On Wed, 26 Apr 2000, Suresh Rajagopalan wrote:

> I am having ARP problems with the 2.2.14 kernel.  
> 
> The configuration shown below on a real server does not supress arp on the
> VIP. A ping from the LAN gets a reply from the real server.  
> 
> I've followed the instructions in the howto, but this one seems not to
> want to work.

        Can you test with tcpdump -e ? Check if the src MAC is from
the real server. And if you ping the real server when the dummy0 is
down, VIP is still configured. Use ifconfig $dev 0.0.0.0 down.
May be another real server is in this state?

        And ping can work even when the dummy0 is hidden. If
you have ARP entry for the real server it is used from the ping.
May be you just moved the VIP from eth0 to dummy0 in the real server and
forgot to remove the ARP entry in the client? When moving VIP between
hosts never forget to arp -d VIP before ping VIP!

        And don't ping from another real server!

        The next step: try to find the bug in the ARP code :) I'm sure,
You will not reach this step :)

> 
> Thanks
> -Suresh
> 
> 
> 
> ------------------------------
> echo "Configuring for LVS-DR"
> 
> VIP=206.117.210.95
> NM=255.255.255.255
> dev=dummy0
> 
> ifconfig $dev up
> sleep 3
> echo 1 > /proc/sys/net/ipv4/ip_forward
> echo 1 > /proc/sys/net/ipv4/conf/all/hidden
> echo 1 > /proc/sys/net/ipv4/conf/dummy0/hidden
> 
> ifconfig $dev $VIP netmask $NM up
> route add -host $VIP dev $dev



Regards

--
Julian Anastasov <uli@xxxxxxxxxxxxxxxxxxxxxx>



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