Hi all, I have two nodes, connected to a switch, using Tinc 1.1 from git. They connect each other with sptps, and to other nodes in the Internet with old protocol because they have Tinc 1.0. There is no problem with remote nodes, but between my 2 local nodes, they see 1518 PMTU. But local network is 1500 MTU !!! So nodes can ping each other but larger data does not go. test1=sllm1 test2=sllm2 test1:/usr/src/tinc# tinc -n coppint info sllm2 Node: sllm2 Address: 192.168.0.202 port 655 Online since: 2014-02-25 13:36:39 Status: validkey visited reachable sptps udp_confirmed Options: pmtu_discovery clamp_mss Protocol: 17.3 Reachability: directly with UDP PMTU: 1518 Edges: host1 host3 host4 host6 sllm1 Subnets: 1a:26:ce:e3:fb:13 6e:de:af:13:55:bf root at test2:~# tinc -n coppint info sllm1 Node: sllm1 Address: 192.168.0.200 port 655 Online since: 2014-02-25 13:36:39 Status: validkey visited reachable sptps udp_confirmed Options: pmtu_discovery clamp_mss Protocol: 17.3 Reachability: directly with UDP PMTU: 1518 Edges: host1 host3 host4 host6 sllm2 Subnets: 12:a5:76:ae:f6:d1 16:5c:d3:3:89:e6 aa:43:ea:86:94:19 c2:3a:f:4a:bd:2c c2:a9:10:51:bd:3e de:ad:ac:cf:a4:ad f2:7e:b:6f:98:48 I did -d5 in Tinc daemon but I see nothing interesting: root at test2:~# cat /var/log/tinc-coppint.log | grep PMTU 2014-02-25 13:31:18 tinc.coppint[413140]: Increase in PMTU to sllm1 (192.168.0.200 port 655) detected, restarting PMTU discovery What do I have to look for in this file ? Host config contains only Address, Cipher, Digest and MACLength; but I think that 3 last are rewritten by sptps. Tinc config is : AddressFamily = ipv4 #BindToInterface = vmbr1 Broadcast = mst ConnectTo = host1 ConnectTo = host2 ConnectTo = host3 ConnectTo = host4 ConnectTo = host5 ConnectTo = host6 ConnectTo = sllm1 Forwarding = internal GraphDumpFile = /tmp/tinc-graph Mode = switch Name = sllm2 PrivateKeyFile = /etc/tinc/coppint/rsa_key.priv ProcessPriority = high What do you think my problem is ? Thank you a lot for your help.
I saw that in logs: 2014-02-25 13:59:53 tinc.coppint[418862]: Sending MTU probe length 1518 to sllm1 (192.168.0.200 port 655) 2014-02-25 13:59:53 tinc.coppint[418862]: Got type 2 MTU probe reply 1518 from sllm1 (192.168.0.200 port 655) How is it possible ?
Even if I put PMTU = 1450 PMTUDiscovery = no in both configuration files, PMTU comes back to 1518 after a few minutes... :(
On Tue, Feb 25, 2014 at 01:53:51PM +0100, Florent Bautista wrote:> I have two nodes, connected to a switch, using Tinc 1.1 from git. > > They connect each other with sptps, and to other nodes in the Internet > with old protocol because they have Tinc 1.0. > > There is no problem with remote nodes, but between my 2 local nodes, > they see 1518 PMTU. But local network is 1500 MTU !!! So nodes can ping > each other but larger data does not go.That is strange, when the network has a MTU of 1500, tinc should detect a PMTU of 1451. I cannot reproduce the problem you have. Could it be that those two nodes are running inside a VM or that you have jumbo frames enabled on the local network?> I did -d5 in Tinc daemon but I see nothing interesting: > > root at test2:~# cat /var/log/tinc-coppint.log | grep PMTU > 2014-02-25 13:31:18 tinc.coppint[413140]: Increase in PMTU to sllm1 > (192.168.0.200 port 655) detected, restarting PMTU discoveryHm, that is somewhat interesting, normally you would not expect the MTU of the local network to change.> Host config contains only Address, Cipher, Digest and MACLength; but I > think that 3 last are rewritten by sptps.That's correct. -- Met vriendelijke groet / with kind regards, Guus Sliepen <guus at tinc-vpn.org> -------------- next part -------------- A non-text attachment was scrubbed... Name: signature.asc Type: application/pgp-signature Size: 181 bytes Desc: Digital signature URL: <http://www.tinc-vpn.org/pipermail/tinc/attachments/20140226/ed028dce/attachment.sig>