Mailing List Archive: [lvs-users] In DR mode, source IP address of real servers' reply packets are different

[lvs-users] In DR mode, source IP address of real servers' reply packets are different

Feb 24, 2013, 7:32 PM

Post #1 of 4 (1428 views)

hi ,dear all
I met one problem of LVS DR mode issue last day.
All packets could be received by the LVS Director, and be directed to
Real Servers. But when Real Server replying, I used "tcpdump" to check the
pakcets and found there are some differences with the source IP address of
the rely-packets.
In one real server (server A: 192.168.0.111), the reply-packets'
source IP address are the Real server IP(192.168.0.111).
but in the other real server (server B: 192.168.0.112), the
reply-packets' source IP address are the Virtual server IP(192.168.0.250).

I was wondering that, what settings induced that? If I want to
achieve case B , how to set them?

thanks,
para
_______________________________________________
Please read the documentation before posting - it's available at:
http://www.linuxvirtualserver.org/

LinuxVirtualServer.org mailing list - lvs-users@LinuxVirtualServer.org
Send requests to lvs-users-request@LinuxVirtualServer.org
or go to http://lists.graemef.net/mailman/listinfo/lvs-users

Re: [lvs-users] In DR mode, source IP address of real servers' reply packets are different [ In reply to ]

khosrow.ebrahimpour at ssc-spc

Feb 27, 2013, 5:08 AM

Post #2 of 4 (1377 views)

Permalink

Hi,

On Monday, February 25, 2013 11:32:54 AM feng zheng wrote:
> hi ,dear all
> I met one problem of LVS DR mode issue last day.
> All packets could be received by the LVS Director, and be directed to
> Real Servers. But when Real Server replying, I used "tcpdump" to check the
> pakcets and found there are some differences with the source IP address of
> the rely-packets.
> In one real server (server A: 192.168.0.111), the reply-packets'
> source IP address are the Real server IP(192.168.0.111).
> but in the other real server (server B: 192.168.0.112), the
> reply-packets' source IP address are the Virtual server IP(192.168.0.250).
>
> I was wondering that, what settings induced that? If I want to
> achieve case B , how to set them?
>
> thanks,
> para

Have you resolved the ARP problem on the real servers? Have a look at
http://www.linuxvirtualserver.org/docs/arp.html for a number of solutions to
the problem.

_______________________________________________
Please read the documentation before posting - it's available at:
http://www.linuxvirtualserver.org/

LinuxVirtualServer.org mailing list - lvs-users@LinuxVirtualServer.org
Send requests to lvs-users-request@LinuxVirtualServer.org
or go to http://lists.graemef.net/mailman/listinfo/lvs-users

Re: [lvs-users] In DR mode, source IP address of real servers' reply packets are different [ In reply to ]

malcolm at loadbalancer

Feb 27, 2013, 5:19 AM

Post #3 of 4 (1370 views)

Permalink

>
> Have you resolved the ARP problem on the real servers? Have a look at
> http://www.linuxvirtualserver.org/docs/arp.html for a number of solutions to
> the problem.
>

I would bet that the loopback/arptables method would reply as the VIP,
and the iptables REDIRECT method would reply as the RIP...

But I'd be interested to know for certain, as I've often wondered if
it could be controlled....

--
Regards,

Malcolm Turnbull.

Loadbalancer.org Ltd.
Phone: +44 (0)870 443 8779
http://www.loadbalancer.org/

_______________________________________________
Please read the documentation before posting - it's available at:
http://www.linuxvirtualserver.org/

LinuxVirtualServer.org mailing list - lvs-users@LinuxVirtualServer.org
Send requests to lvs-users-request@LinuxVirtualServer.org
or go to http://lists.graemef.net/mailman/listinfo/lvs-users

Re: [lvs-users] In DR mode, source IP address of real servers' reply packets are different [ In reply to ]

zf5984599 at gmail

Feb 27, 2013, 7:35 PM

Post #4 of 4 (1355 views)

Permalink

2013/2/27 Malcolm Turnbull <malcolm@loadbalancer.org>

> >
> > Have you resolved the ARP problem on the real servers? Have a look at
> > http://www.linuxvirtualserver.org/docs/arp.html for a number of
> solutions to
> > the problem.
> >
>
> I would bet that the loopback/arptables method would reply as the VIP,
> and the iptables REDIRECT method would reply as the RIP...
>
> How to use VIP as the reply src ip addr?

> But I'd be interested to know for certain, as I've often wondered if
> it could be controlled....
>
>
> --
> Regards,
>
> Malcolm Turnbull.
>
> Loadbalancer.org Ltd.
> Phone: +44 (0)870 443 8779
> http://www.loadbalancer.org/
>
> _______________________________________________
> Please read the documentation before posting - it's available at:
> http://www.linuxvirtualserver.org/
>
> LinuxVirtualServer.org mailing list - lvs-users@LinuxVirtualServer.org
> Send requests to lvs-users-request@LinuxVirtualServer.org
> or go to http://lists.graemef.net/mailman/listinfo/lvs-users
>
_______________________________________________
Please read the documentation before posting - it's available at:
http://www.linuxvirtualserver.org/

LinuxVirtualServer.org mailing list - lvs-users@LinuxVirtualServer.org
Send requests to lvs-users-request@LinuxVirtualServer.org
or go to http://lists.graemef.net/mailman/listinfo/lvs-users