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Re: icmp-redirects, hung connection, tcpdump

To: Michael E Brown <michael_e_brown@xxxxxxxx>
Subject: Re: icmp-redirects, hung connection, tcpdump
Cc: <lvs-users@xxxxxxxxxxxxxxxxxxxxxx>, Joseph Mack <mack@xxxxxxxxxxx>, "Justin M. Mahoney" <justin@xxxxxxxxxxxxxxxxxxxx>, <michael_e_brown@xxxxxxxxxxxxxxxxx>
From: Julian Anastasov <ja@xxxxxx>
Date: Fri, 12 Jan 2001 21:31:35 +0000 (GMT)
        Hello,

On Fri, 12 Jan 2001, Michael E Brown wrote:

> On Fri, 12 Jan 2001, Julian Anastasov wrote:
> >
> >     Yes, if all/send_redirects is 1 every <device>/send_redirects
> > is ignored. So, if we leave it 1 redirects are sent. To stop them we
> > need all=0 && <device>=0. default/send_redirects is the value that will
> > be inherited from each new interface that is created.
>
>
> How about a patch to the HOWTO? This way, the unwary cannot get into
> trouble...

        Yes, may be something like this:

--- LVS_2.2.13-HOWTO.orig       Wed Dec  1 05:58:51 1999
+++ LVS_2.2.13-HOWTO    Fri Jan 12 21:23:36 2001
@@ -4651,7 +4651,7 @@
 doesn't need to pass through a router to reach the LVS, you won't
 have such a symptom. :)

-Only when LVS/DR is used and there is only one interface to
+Only when LVS/DR and LVS/NAT are used and there is only one interface to
 receive packets for VIP and to connect the real server, there is
 a need to suppress the ICMP redirects of the interface.

@@ -4659,8 +4659,13 @@
 The configure.pl script turns off icmp redirects on the director
 using sysctl

+    echo 0 > /proc/sys/net/ipv4/conf/all/send_redirects
+    echo 0 > /proc/sys/net/ipv4/conf/default/send_redirects
     echo 0 > /proc/sys/net/ipv4/conf/eth0/send_redirects
 )
+
+Starting from LVS 0.9.4 the ICMP redirect for LVS/DR method is
+suppressed but the problems remains for LVS/NAT.

 (Wensong)
 In the reverse direction, replies coming back from the realserver


        But may be I have an old version of this HOWTO, so please
make another patch from the both pieces. I assume I'm right that the
problem exists for the LVS/NAT method too. May be this needs testing.

> --- LVS-HOWTO-991205  Thu Jan 11 16:31:25 2001
> +++ LVS-HOWTO-MEB     Fri Jan 12 12:58:01 2001
> @@ -9,6 +9,7 @@
>  v0.7 1 Dec 99, fixes to "arp problem" write up
>                  (no updates needed for LVS v0.9.5, 29Nov99 release)
>  v0.8 3 Dec 99, Horms' method added for VS-DR
> +v0.8.1  12 Jan 01 mebrown added info for conf/all/send_redirects
>
>  comments/feedback/fixes/contributions to Joe
>
> @@ -4875,6 +4876,8 @@
>  The configure.pl script turns off icmp redirects on the director
>  using sysctl
>
> +    echo 0 > /proc/sys/net/ipv4/conf/all/send_redirects
> +    echo 0 > /proc/sys/net/ipv4/conf/default/send_redirects
>      echo 0 > /proc/sys/net/ipv4/conf/eth0/send_redirects
>  )


Regards

--
Julian Anastasov <ja@xxxxxx>



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