* "ping6 -M do" fragments packets
@ 2007-10-12 15:18 Chuck Anderson
2007-10-12 16:00 ` Patrick McHardy
0 siblings, 1 reply; 4+ messages in thread
From: Chuck Anderson @ 2007-10-12 15:18 UTC (permalink / raw)
To: netdev
I'm not subscribed, so please Cc: me on any responses. Thanks.
According to the man page, ping6 should support the "-M do" option so
never fragment packets, which I'd like to use for testing the MTU of a
path. This option works fine for IPv4 ping, but doesn't work with
IPv6 ping6. I can guarantee that I don't have an MTU of 63356 :-)
>ping6 -M do -s 65527 www.kame.net
PING www.kame.net(orange.kame.net) 65527 data bytes
65535 bytes from orange.kame.net: icmp_seq=1 ttl=49 time=224 ms
65535 bytes from orange.kame.net: icmp_seq=2 ttl=49 time=226 ms
65535 bytes from orange.kame.net: icmp_seq=3 ttl=49 time=224 ms
--- www.kame.net ping statistics ---
3 packets transmitted, 3 received, 0% packet loss, time 1999ms
rtt min/avg/max/mdev = 224.118/225.270/226.909/1.251 ms
Sure enough, wireshark reports fragments:
No. Time Source Destination Protocol Info
1 0.000000 2001:468:616:8c9:213:72ff:fe74:da15 2001:200:0:8002:203:47ff:fea5:3085 IPv6 IPv6 fragment (nxt=ICMPv6 (0x3a) off=0 id=0x79)
2 0.000007 2001:468:616:8c9:213:72ff:fe74:da15 2001:200:0:8002:203:47ff:fea5:3085 IPv6 IPv6 fragment (nxt=ICMPv6 (0x3a) off=1448 id=0x79)
3 0.000010 2001:468:616:8c9:213:72ff:fe74:da15 2001:200:0:8002:203:47ff:fea5:3085 IPv6 IPv6 fragment (nxt=ICMPv6 (0x3a) off=2896 id=0x79)
4 0.000013 2001:468:616:8c9:213:72ff:fe74:da15 2001:200:0:8002:203:47ff:fea5:3085 IPv6 IPv6 fragment (nxt=ICMPv6 (0x3a) off=4344 id=0x79)
5 0.000015 2001:468:616:8c9:213:72ff:fe74:da15 2001:200:0:8002:203:47ff:fea5:3085 IPv6 IPv6 fragment (nxt=ICMPv6 (0x3a) off=5792 id=0x79)
6 0.000018 2001:468:616:8c9:213:72ff:fe74:da15 2001:200:0:8002:203:47ff:fea5:3085 IPv6 IPv6 fragment (nxt=ICMPv6 (0x3a) off=7240 id=0x79)
Is this a known issue, or some issue with the Fedora build I'm using?
iputils-20070202-3.fc7
Thanks.
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: "ping6 -M do" fragments packets
2007-10-12 15:18 "ping6 -M do" fragments packets Chuck Anderson
@ 2007-10-12 16:00 ` Patrick McHardy
2007-10-12 16:32 ` Chuck Anderson
0 siblings, 1 reply; 4+ messages in thread
From: Patrick McHardy @ 2007-10-12 16:00 UTC (permalink / raw)
To: Chuck Anderson; +Cc: netdev
Chuck Anderson wrote:
> I'm not subscribed, so please Cc: me on any responses. Thanks.
>
> According to the man page, ping6 should support the "-M do" option so
> never fragment packets, which I'd like to use for testing the MTU of a
> path. This option works fine for IPv4 ping, but doesn't work with
> IPv6 ping6. I can guarantee that I don't have an MTU of 63356 :-)
>
>
>>ping6 -M do -s 65527 www.kame.net
>
> Sure enough, wireshark reports fragments:
>
> No. Time Source Destination Protocol Info
> 1 0.000000 2001:468:616:8c9:213:72ff:fe74:da15 2001:200:0:8002:203:47ff:fea5:3085 IPv6 IPv6 fragment (nxt=ICMPv6 (0x3a) off=0 id=0x79)
> 2 0.000007 2001:468:616:8c9:213:72ff:fe74:da15 2001:200:0:8002:203:47ff:fea5:3085 IPv6 IPv6 fragment (nxt=ICMPv6 (0x3a) off=1448 id=0x79)
Are you using nf_conntrack_ipv6?
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: "ping6 -M do" fragments packets
2007-10-12 16:00 ` Patrick McHardy
@ 2007-10-12 16:32 ` Chuck Anderson
2007-10-12 17:17 ` Patrick McHardy
0 siblings, 1 reply; 4+ messages in thread
From: Chuck Anderson @ 2007-10-12 16:32 UTC (permalink / raw)
To: Patrick McHardy; +Cc: netdev
On Fri, Oct 12, 2007 at 06:00:12PM +0200, Patrick McHardy wrote:
> >>ping6 -M do -s 65527 www.kame.net
> >
> > Sure enough, wireshark reports fragments:
> >
> > No. Time Source Destination Protocol Info
> > 1 0.000000 2001:468:616:8c9:213:72ff:fe74:da15 2001:200:0:8002:203:47ff:fea5:3085 IPv6 IPv6 fragment (nxt=ICMPv6 (0x3a) off=0 id=0x79)
> > 2 0.000007 2001:468:616:8c9:213:72ff:fe74:da15 2001:200:0:8002:203:47ff:fea5:3085 IPv6 IPv6 fragment (nxt=ICMPv6 (0x3a) off=1448 id=0x79)
>
> Are you using nf_conntrack_ipv6?
No:
nf_conntrack_tftp 9813 0
nf_conntrack_netbios_ns 7105 0
ipt_LOG 10305 1
nf_conntrack_ipv4 15049 6
xt_state 6593 6
nf_conntrack 61001 4 nf_conntrack_tftp,nf_conntrack_netbios_ns,nf_conntrack_ipv4,xt_state
nfnetlink 10841 2 nf_conntrack_ipv4,nf_conntrack
ipt_REJECT 8641 4
iptable_filter 6977 1
ip_tables 16389 1 iptable_filter
ip6t_LOG 10945 1
ip6t_REJECT 9537 2
ip6table_filter 6849 1
ip6_tables 17541 2 ip6t_LOG,ip6table_filter
x_tables 18757 8 ipt_LOG,xt_state,ipt_REJECT,ip_tables,ip6t_LOG,ip6t_REJECT,ip6_tables,xt_tcpudp
ipv6 276673 51 ip6t_REJECT
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: "ping6 -M do" fragments packets
2007-10-12 16:32 ` Chuck Anderson
@ 2007-10-12 17:17 ` Patrick McHardy
0 siblings, 0 replies; 4+ messages in thread
From: Patrick McHardy @ 2007-10-12 17:17 UTC (permalink / raw)
To: Chuck Anderson; +Cc: netdev
Chuck Anderson wrote:
> On Fri, Oct 12, 2007 at 06:00:12PM +0200, Patrick McHardy wrote:
>
>>>>ping6 -M do -s 65527 www.kame.net
>>>
>>>Sure enough, wireshark reports fragments:
>>>
>>>No. Time Source Destination Protocol Info
>>> 1 0.000000 2001:468:616:8c9:213:72ff:fe74:da15 2001:200:0:8002:203:47ff:fea5:3085 IPv6 IPv6 fragment (nxt=ICMPv6 (0x3a) off=0 id=0x79)
>>> 2 0.000007 2001:468:616:8c9:213:72ff:fe74:da15 2001:200:0:8002:203:47ff:fea5:3085 IPv6 IPv6 fragment (nxt=ICMPv6 (0x3a) off=1448 id=0x79)
>>
>>Are you using nf_conntrack_ipv6?
>
>
> No:
>
> [...]
Works for me:
$ ping6 -M do -s 65527 www.kame.net -n -c 1
PING www.kame.net(2001:200:0:8002:203:47ff:fea5:3085) 65527 data bytes
>From 2001:6f8:974:0:21b:21ff:fe02:6fad icmp_seq=1 Packet too big: mtu=1500
--- www.kame.net ping statistics ---
0 packets transmitted, 0 received, +1 errors
^ permalink raw reply [flat|nested] 4+ messages in thread
end of thread, other threads:[~2007-10-12 17:18 UTC | newest]
Thread overview: 4+ messages (download: mbox.gz follow: Atom feed
-- links below jump to the message on this page --
2007-10-12 15:18 "ping6 -M do" fragments packets Chuck Anderson
2007-10-12 16:00 ` Patrick McHardy
2007-10-12 16:32 ` Chuck Anderson
2007-10-12 17:17 ` Patrick McHardy
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).