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Re: [lvs-users] question about LVS

To: "LinuxVirtualServer.org users mailing list." <lvs-users@xxxxxxxxxxxxxxxxxxxxxx>
Subject: Re: [lvs-users] question about LVS
Cc: "LinuxVirtualServer.org users mailing list." <lvs-users@xxxxxxxxxxxxxxxxxxxxxx>
From: mve@xxxxxxxxxxxxxxxxx
Date: Tue, 4 May 2010 20:30:28 +0200 (CEST)
> On Tue, 2010-05-04 at 15:48 +0200, Michiel van Es wrote:
>> I am trying iptables -F but then no connection is made to the real
>> server (server1).
>> I am affraid I only Flush the filter table but not other tables..how can
>> I check this?
>> iptables -L -vn or with arptables?
>>
>
> Disclaimer: i have never used arptables. That said, why are you using
> arptables? I recall both your realservers are running CentOS 5.4 so
> setting the arp_ignore and arp_announce flags should be sufficient to
> handle the ARP problem.

I did not used it, it is being used in several howto's.
I removed the whole package to make sure it isn't used.

>
> Please post the bash script you're using to setup the loopback device
> etc. so i can take a look and maybe adjust it.

echo "0" >/proc/sys/net/ipv4/ip_forward
cat       /proc/sys/net/ipv4/ip_forward
echo 1 > /proc/sys/net/ipv4/conf/eth0/arp_ignore
echo 2 > /proc/sys/net/ipv4/conf/eth0/arp_announce
echo 1 > /proc/sys/net/ipv4/conf/all/arp_ignore
echo 2 > /proc/sys/net/ipv4/conf/all/arp_announce
/sbin/ifconfig lo:110 194.145.200.87 broadcast 194.145.200.87 netmask
0xffffffff up
/sbin/ifconfig lo:110
/sbin/route add -host 194.145.200.87 dev lo:110

I also run this script on server2 in exact the same way.
>
> And since you're running CentOS, issuing:
>
> $ service iptables stop
>
> on all nodes should be enough to clear the firewall rules. Once you got
> your LVS setup working, add rules one at a time, while testing your
> setup and finally issue:
>
> $ service iptables save
>
> once you're satisfied, to save all active rules
> to /etc/sysconfig/iptables.  But for now, let's not add firewall rules
> to further complicate things.

When I stop Iptables orflush them the reaction from the client is
different(as stated before).

With iptables on:
[root@knox01 ~]# telnet 194.145.200.87 25
Trying 194.145.200.87...
telnet: connect to address 194.145.200.87: No route to host
telnet: Unable to connect to remote host: No route to host
[root@knox01 ~]# telnet 194.145.200.87 25

With iptables off (service iptables stop) on server1:
(takes a long time)
Nothing happens:
root@knox01 ~]# telnet 194.145.200.87 25
Trying 194.145.200.87...

Could I run some tcpdumps on real servers and LVS dr to check what is
going wrong?

I think something else is rerouting the packages wrong...but what it is?
route on both real servers are the same.

>
>
> Léon

Michiel
>
>
>
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>
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