Pirana problem with MTU fragmentation

[Andrey Feldman]

Hi.
cat /proc/sys/net/ipv4/ip_no_pmtu_disc ?
tracepath 10.192.6.1 ?
ifconfig -a ?

On 03/08/2012 07:29 PM, Khapare Joshi wrote:
> Hello all,
>
> I am running pulse on virtual machine for webserver, it seems working well, but there is one problem with networking I think. It seems there is a problem with lvs server is not fragmenting larger than 1500 packets size. I did the quick tcpdump and I get following info.
>
>
> my problem is when user is uploading files it takes for ever and never completes. I am thinking lvs (pulse) is not not fragmenting the larger packet size than 1500 hence it never goes to backend server.
>
> 16:25:22.543563 00:1f:6d:cf:4e:49>  52:54:00:b5:30:3c, ethertype IPv4 (0x0800), length 2974: 10.128.1.5.60715>  10.192.6.1.https: Flags [.], seq 7705:10625, ack 146, win 16388, length 2920
> 16:25:22.543590 52:54:00:b5:30:3c>  00:1f:6d:cf:4e:49, ethertype IPv4 (0x0800), length 590: 10.192.6.1>  10.128.1.5  <http://10.128.1.5>: ICMP 130.208.165.177 unreachable - need to frag (mtu 1500), length 556
>
>
> I tested following:
>
> 1. IP forward is enabled.
> 2. lro,gro are off on eth0
> ethtool -k eth0
> Offload parameters for eth0:
> rx-checksumming: on
> tx-checksumming: on
> scatter-gather: on
> tcp-segmentation-offload: on
>
> udp-fragmentation-offload: on
> generic-segmentation-offload: on
> generic-receive-offload: off
> large-receive-offload: off
> 3. IPVS version is v1.2.1
> 4. Backend server has arptables and set to mangaled to right interface
>
> 5. Firewall is allowed on both lvs and backend server.
> 6. http and https are open for all.
>
> Any help in this would be great.
>
> K
>
>
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