Intermittent TCP connect issues when using tinc 1.0.23 and IPv6

[tomp at tomp.co.uk]

Last email was sent to digest accidentally:

Thanks for replying so quickly Guus.

I will try increasing the re-keying time to 86400, and am now running 
the servers in debug 5 mode logging to a file, so will get all output.

Its interesting what you say about UDP being given lower priority, the 
two end points of this VPN are actually within the same data center, but 
are being routed within the DC's core routers (because its going between 
2 different public IP ranges).

When I did a download speed test over HTTP over the VPN, I started to 
see replay window errors (default setting of 128).

Does that perhaps suggest that the DC's routers are re-ordering UDP 
traffic?

Thanks
Tom


On 2013-11-28 14:52, tomp at tomp.co.uk wrote:
> Hi Guus
> 
> Sorry for replying to the digest in my last E-mail.
> 
> Now that debugging is turned on properly, I am seeing some interesting 
> lines:
> 
> 2013-11-28 14:48:48 tinc.dcvpn[31620]: Got type 2 MTU probe reply
> 1431 from rps (2001:1b40:5000:9::2 port 655)
> 2013-11-28 14:48:48 tinc.dcvpn[31620]: Got type 2 MTU probe reply
> 1431 from rps (2001:1b40:5000:9::2 port 655)
> 2013-11-28 14:48:48 tinc.dcvpn[31620]: Got type 2 MTU probe reply
> 1431 from rps (2001:1b40:5000:9::2 port 655)
> 2013-11-28 14:48:48 tinc.dcvpn[31620]: rps (2001:1b40:5000:9::2 port
> 655) RTT 0.49 ms, burst bandwidth 51.684 Mbit/s, rx packet loss 100.00
> %
> 
> Specifically the bit about 100% packet loss.
> 
> It was shortly after following by:
> 
> 2013-11-28 14:51:01 tinc.dcvpn[31620]: Got REQ_KEY from rps
> (2001:1b40:5000:9::2 port 55170): 15 rps rsukmhb 21 AA...
> 
> I got a REQ_KEY request 12 times in 1s from rps.
> 
> Tom
> 
> On 2013-11-28 14:28, tomp at tomp.co.uk wrote:
>> I can confirm this issue is also occurring when using tinc 1.1pre9
>> with elliptic encryption.
>> On 2013-11-28 12:12, tomp at tomp.co.uk wrote:
>>> Here's some more info, as a timeout just occurred using rsync from
>>> rsukmhb to rps sites:
>>> Nov 28 11:59:01 rsuk-mhb-pubweb101 php: ict-pubweb [SyncSites]
>>> (21294) Info: Plugin started
>>> Nov 28 11:59:01 rsuk-mhb-pubweb101 php: ict-pubweb [SyncSites]
>>> (21294) Info: Last sync build time: 2013-11-27 09:50:40
>>> Nov 28 11:59:16 rsuk-mhb-pubweb101 php: ict-pubweb [SyncSites]
>>> (21294) Error: Rsync failed: rsync error: timeout waiting for daemon
>>> connection (code 35) at socket.c(279) [receiver=3.0.6]
>>> Nov 28 11:59:16 rsuk-mhb-pubweb101 php: ict-pubweb [SyncSites]
>>> (21294) Info: Plugin stopped
>>> Rsync is configured with a connection timeout of 15s, so the
>>> connection was started at 11:59:01 and timed out at 11:59:16.
>>> At the same time our import cron process ran from rps to the same
>>> server that was running the rsync client:
>>> Nov 28 11:59:01 rsuk-mhb-pubweb101 httpd: pubweb.infinity.local
>>> rsuk-mhb-pubweb101.ictnw.net 2001:1b40:5600:1::76 - ict-pubweb
>>> [28/Nov/2013:11:59:01 +0000] "GET
>>> /v1/cmsEvents?limit=1000&sort%5B0%5D=rowId-asc&filter%5B0%5D=siteId-in-value-2&filter%5B1%5D=rowId-gt-value-933&filter%5B2%5D=eventType-eq-value-lead
>>> HTTP/1.0" 200 - "-" "Icc HTTP Client"
>>> I am running tinc with debug mode 5 on both firewalls so here is a
>>> sample of the logs from both at that time:
>>> rsukmhb site (where rsync client is):
>>> -----------------------------------------
>>> [thomas.parrott at rsuk-mhb-fw01 ~]$ grep '11:59:' /var/log/messages
>>> Nov 28 11:59:01 rsuk-mhb-fw01 tinc.dcvpn[24911]: Clamping MSS of
>>> packet from rsukmhb to rps to 1369
>>> Nov 28 11:59:01 rsuk-mhb-fw01 tinc.dcvpn[24911]: Sending packet of 
>>> 86
>>> bytes to rps (2001:1b40:5000:9::2 port 655)
>>> Nov 28 11:59:01 rsuk-mhb-fw01 tinc.dcvpn[24911]: Clamping MSS of
>>> packet from rsukmhb to rps to 1369
>>> Nov 28 11:59:01 rsuk-mhb-fw01 tinc.dcvpn[24911]: Sending packet of 
>>> 86
>>> bytes to rps (2001:1b40:5000:9::2 port 655)
>>> Nov 28 11:59:01 rsuk-mhb-fw01 tinc.dcvpn[24911]: Sending packet of 
>>> 74
>>> bytes to rps (2001:1b40:5000:9::2 port 655)
>>> Nov 28 11:59:01 rsuk-mhb-fw01 tinc.dcvpn[24911]: Sending packet of
>>> 224 bytes to rps (2001:1b40:5000:9::2 port 655)
>>> Nov 28 11:59:01 rsuk-mhb-fw01 tinc.dcvpn[24911]: Sending packet of 
>>> 74
>>> bytes to rps (2001:1b40:5000:9::2 port 655)
>>> Nov 28 11:59:01 rsuk-mhb-fw01 tinc.dcvpn[24911]: Sending packet of 
>>> 74
>>> bytes to rps (2001:1b40:5000:9::2 port 655)
>>> Nov 28 11:59:01 rsuk-mhb-fw01 tinc.dcvpn[24911]: Clamping MSS of
>>> packet from rsukmhb to rps to 1369
>>> Nov 28 11:59:01 rsuk-mhb-fw01 tinc.dcvpn[24911]: Sending packet of 
>>> 86
>>> bytes to rps (2001:1b40:5000:9::2 port 655)
>>> Nov 28 11:59:01 rsuk-mhb-fw01 tinc.dcvpn[24911]: Sending packet of 
>>> 74
>>> bytes to rps (2001:1b40:5000:9::2 port 655)
>>> Nov 28 11:59:01 rsuk-mhb-fw01 tinc.dcvpn[24911]: Sending packet of 
>>> 88
>>> bytes to rps (2001:1b40:5000:9::2 port 655)
>>> Nov 28 11:59:01 rsuk-mhb-fw01 tinc.dcvpn[24911]: Sending packet of 
>>> 74
>>> bytes to rps (2001:1b40:5000:9::2 port 655)
>>> Nov 28 11:59:01 rsuk-mhb-fw01 tinc.dcvpn[24911]: Sending packet of 
>>> 87
>>> bytes to rps (2001:1b40:5000:9::2 port 655)
>>> Nov 28 11:59:01 rsuk-mhb-fw01 tinc.dcvpn[24911]: Sending packet of
>>> 108 bytes to rps (2001:1b40:5000:9::2 port 655)
>>> Nov 28 11:59:01 rsuk-mhb-fw01 tinc.dcvpn[24911]: Sending packet of 
>>> 82
>>> bytes to rps (2001:1b40:5000:9::2 port 655)
>>> Nov 28 11:59:01 rsuk-mhb-fw01 tinc.dcvpn[24911]: Sending packet of
>>> 136 bytes to rps (2001:1b40:5000:9::2 port 655)
>>> Nov 28 11:59:02 rsuk-mhb-fw01 tinc.dcvpn[24911]: Sending packet of 
>>> 74
>>> bytes to rps (2001:1b40:5000:9::2 port 655)
>>> Nov 28 11:59:02 rsuk-mhb-fw01 tinc.dcvpn[24911]: Sending packet of 
>>> 74
>>> bytes to rps (2001:1b40:5000:9::2 port 655)
>>> Nov 28 11:59:02 rsuk-mhb-fw01 tinc.dcvpn[24911]: Sending packet of 
>>> 82
>>> bytes to rps (2001:1b40:5000:9::2 port 655)
>>> Nov 28 11:59:02 rsuk-mhb-fw01 tinc.dcvpn[24911]: Sending packet of 
>>> 74
>>> bytes to rps (2001:1b40:5000:9::2 port 655)
>>> Nov 28 11:59:02 rsuk-mhb-fw01 tinc.dcvpn[24911]: Sending packet of 
>>> 74
>>> bytes to rps (2001:1b40:5000:9::2 port 655)
>>> Nov 28 11:59:02 rsuk-mhb-fw01 tinc.dcvpn[24911]: Sending packet of 
>>> 74
>>> bytes to rps (2001:1b40:5000:9::2 port 655)
>>> Nov 28 11:59:02 rsuk-mhb-fw01 tinc.dcvpn[24911]: Sending packet of 
>>> 79
>>> bytes to rps (2001:1b40:5000:9::2 port 655)
>>> Nov 28 11:59:02 rsuk-mhb-fw01 tinc.dcvpn[24911]: Sending packet of 
>>> 74
>>> bytes to rps (2001:1b40:5000:9::2 port 655)
>>> Nov 28 11:59:02 rsuk-mhb-fw01 tinc.dcvpn[24911]: Sending packet of 
>>> 74
>>> bytes to rps (2001:1b40:5000:9::2 port 655)
>>> Nov 28 11:59:02 rsuk-mhb-fw01 tinc.dcvpn[24911]: Sending packet of 
>>> 74
>>> bytes to rps (2001:1b40:5000:9::2 port 655)
>>> Nov 28 11:59:02 rsuk-mhb-fw01 tinc.dcvpn[24911]: Sending packet of 
>>> 89
>>> bytes to rps (2001:1b40:5000:9::2 port 655)
>>> Nov 28 11:59:02 rsuk-mhb-fw01 tinc.dcvpn[24911]: Sending packet of 
>>> 89
>>> bytes to rps (2001:1b40:5000:9::2 port 655)
>>> Nov 28 11:59:02 rsuk-mhb-fw01 tinc.dcvpn[24911]: Sending packet of 
>>> 74
>>> bytes to rps (2001:1b40:5000:9::2 port 655)
>>> Nov 28 11:59:02 rsuk-mhb-fw01 tinc.dcvpn[24911]: Sending packet of 
>>> 74
>>> bytes to rps (2001:1b40:5000:9::2 port 655)
>>> Nov 28 11:59:02 rsuk-mhb-fw01 tinc.dcvpn[24911]: Sending packet of 
>>> 80
>>> bytes to rps (2001:1b40:5000:9::2 port 655)
>>> Nov 28 11:59:02 rsuk-mhb-fw01 tinc.dcvpn[24911]: Clamping MSS of
>>> packet from rsukmhb to rps to 1369
>>> Nov 28 11:59:02 rsuk-mhb-fw01 tinc.dcvpn[24911]: Sending packet of 
>>> 86
>>> bytes to rps (2001:1b40:5000:9::2 port 655)
>>> Nov 28 11:59:02 rsuk-mhb-fw01 tinc.dcvpn[24911]: Sending packet of 
>>> 74
>>> bytes to rps (2001:1b40:5000:9::2 port 655)
>>> Nov 28 11:59:02 rsuk-mhb-fw01 tinc.dcvpn[24911]: Sending packet of 
>>> 74
>>> bytes to rps (2001:1b40:5000:9::2 port 655)
>>> Nov 28 11:59:02 rsuk-mhb-fw01 tinc.dcvpn[24911]: Sending packet of 
>>> 79
>>> bytes to rps (2001:1b40:5000:9::2 port 655)
>>> Nov 28 11:59:02 rsuk-mhb-fw01 tinc.dcvpn[24911]: Sending packet of 
>>> 74
>>> bytes to rps (2001:1b40:5000:9::2 port 655)
>>> Nov 28 11:59:03 rsuk-mhb-fw01 tinc.dcvpn[24911]: Sending packet of
>>> 139 bytes to rps (2001:1b40:5000:9::2 port 655)
>>> Nov 28 11:59:04 rsuk-mhb-fw01 tinc.dcvpn[24911]: Clamping MSS of
>>> packet from rsukmhb to rps to 1369
>>> Nov 28 11:59:04 rsuk-mhb-fw01 tinc.dcvpn[24911]: Sending packet of 
>>> 86
>>> bytes to rps (2001:1b40:5000:9::2 port 655)
>>> Nov 28 11:59:08 rsuk-mhb-fw01 tinc.dcvpn[24911]: Clamping MSS of
>>> packet from rsukmhb to rps to 1369
>>> Nov 28 11:59:08 rsuk-mhb-fw01 tinc.dcvpn[24911]: Sending packet of 
>>> 86
>>> bytes to rps (2001:1b40:5000:9::2 port 655)
>>> Nov 28 11:59:10 rsuk-mhb-fw01 tinc.dcvpn[24911]: Sending packet of
>>> 118 bytes to rps (2001:1b40:5000:9::2 port 655)
>>> Nov 28 11:59:11 rsuk-mhb-fw01 tinc.dcvpn[24911]: Sending packet of
>>> 118 bytes to rps (2001:1b40:5000:9::2 port 655)
>>> Nov 28 11:59:11 rsuk-mhb-fw01 tinc.dcvpn[24911]: Clamping MSS of
>>> packet from rsukmhb to rps to 1369
>>> Nov 28 11:59:11 rsuk-mhb-fw01 tinc.dcvpn[24911]: Sending packet of 
>>> 86
>>> bytes to rps (2001:1b40:5000:9::2 port 655)
>>> Nov 28 11:59:11 rsuk-mhb-fw01 tinc.dcvpn[24911]: Sending packet of 
>>> 74
>>> bytes to rps (2001:1b40:5000:9::2 port 655)
>>> Nov 28 11:59:11 rsuk-mhb-fw01 tinc.dcvpn[24911]: Sending packet of
>>> 224 bytes to rps (2001:1b40:5000:9::2 port 655)
>>> Nov 28 11:59:11 rsuk-mhb-fw01 tinc.dcvpn[24911]: Sending packet of 
>>> 74
>>> bytes to rps (2001:1b40:5000:9::2 port 655)
>>> Nov 28 11:59:11 rsuk-mhb-fw01 tinc.dcvpn[24911]: Sending packet of 
>>> 74
>>> bytes to rps (2001:1b40:5000:9::2 port 655)
>>> Nov 28 11:59:12 rsuk-mhb-fw01 tinc.dcvpn[24911]: Sending packet of
>>> 118 bytes to rps (2001:1b40:5000:9::2 port 655)
>>> Nov 28 11:59:13 rsuk-mhb-fw01 tinc.dcvpn[24911]: Sending packet of
>>> 118 bytes to rps (2001:1b40:5000:9::2 port 655)
>>> Nov 28 11:59:14 rsuk-mhb-fw01 tinc.dcvpn[24911]: Sending packet of
>>> 118 bytes to rps (2001:1b40:5000:9::2 port 655)
>>> Nov 28 11:59:16 rsuk-mhb-fw01 tinc.dcvpn[24911]: Clamping MSS of
>>> packet from rsukmhb to rps to 1369
>>> Nov 28 11:59:16 rsuk-mhb-fw01 tinc.dcvpn[24911]: Sending packet of 
>>> 86
>>> bytes to rps (2001:1b40:5000:9::2 port 655)
>>> Nov 28 11:59:21 rsuk-mhb-fw01 tinc.dcvpn[24911]: Clamping MSS of
>>> packet from rsukmhb to rps to 1369
>>> Nov 28 11:59:21 rsuk-mhb-fw01 tinc.dcvpn[24911]: Sending packet of 
>>> 86
>>> bytes to rps (2001:1b40:5000:9::2 port 655)
>>> Nov 28 11:59:21 rsuk-mhb-fw01 tinc.dcvpn[24911]: Sending packet of 
>>> 74
>>> bytes to rps (2001:1b40:5000:9::2 port 655)
>>> Nov 28 11:59:21 rsuk-mhb-fw01 tinc.dcvpn[24911]: Sending packet of
>>> 224 bytes to rps (2001:1b40:5000:9::2 port 655)
>>> Nov 28 11:59:21 rsuk-mhb-fw01 tinc.dcvpn[24911]: Sending packet of 
>>> 74
>>> bytes to rps (2001:1b40:5000:9::2 port 655)
>>> Nov 28 11:59:21 rsuk-mhb-fw01 tinc.dcvpn[24911]: Sending packet of 
>>> 74
>>> bytes to rps (2001:1b40:5000:9::2 port 655)
>>> Nov 28 11:59:29 rsuk-mhb-fw01 tinc.dcvpn[24911]: Clamping MSS of
>>> packet from rsukmhb to rps to 1369
>>> Nov 28 11:59:29 rsuk-mhb-fw01 tinc.dcvpn[24911]: Sending packet of 
>>> 86
>>> bytes to rps (2001:1b40:5000:9::2 port 655)
>>> Nov 28 11:59:29 rsuk-mhb-fw01 tinc.dcvpn[24911]: Sending packet of 
>>> 74
>>> bytes to rps (2001:1b40:5000:9::2 port 655)
>>> Nov 28 11:59:29 rsuk-mhb-fw01 tinc.dcvpn[24911]: Sending packet of
>>> 224 bytes to rps (2001:1b40:5000:9::2 port 655)
>>> Nov 28 11:59:29 rsuk-mhb-fw01 tinc.dcvpn[24911]: Sending packet of 
>>> 74
>>> bytes to rps (2001:1b40:5000:9::2 port 655)
>>> Nov 28 11:59:29 rsuk-mhb-fw01 tinc.dcvpn[24911]: Sending packet of 
>>> 74
>>> bytes to rps (2001:1b40:5000:9::2 port 655)
>>> Nov 28 11:59:34 rsuk-mhb-fw01 tinc.dcvpn[24911]: Sending packet of
>>> 129 bytes to rps (2001:1b40:5000:9::2 port 655)
>>> Nov 28 11:59:39 rsuk-mhb-fw01 tinc.dcvpn[24911]: Clamping MSS of
>>> packet from rsukmhb to rps to 1369
>>> Nov 28 11:59:39 rsuk-mhb-fw01 tinc.dcvpn[24911]: Sending packet of 
>>> 86
>>> bytes to rps (2001:1b40:5000:9::2 port 655)
>>> Nov 28 11:59:39 rsuk-mhb-fw01 tinc.dcvpn[24911]: Sending packet of 
>>> 74
>>> bytes to rps (2001:1b40:5000:9::2 port 655)
>>> Nov 28 11:59:39 rsuk-mhb-fw01 tinc.dcvpn[24911]: Sending packet of
>>> 224 bytes to rps (2001:1b40:5000:9::2 port 655)
>>> Nov 28 11:59:39 rsuk-mhb-fw01 tinc.dcvpn[24911]: Sending packet of 
>>> 74
>>> bytes to rps (2001:1b40:5000:9::2 port 655)
>>> Nov 28 11:59:39 rsuk-mhb-fw01 tinc.dcvpn[24911]: Sending packet of 
>>> 74
>>> bytes to rps (2001:1b40:5000:9::2 port 655)
>>> Nov 28 11:59:42 rsuk-mhb-fw01 tinc.dcvpn[24911]: Got MTU probe 
>>> length
>>> 1443 from rps (2001:1b40:5000:9::2 port 655)
>>> Nov 28 11:59:42 rsuk-mhb-fw01 tinc.dcvpn[24911]: Got MTU probe 
>>> length
>>> 1443 from rps (2001:1b40:5000:9::2 port 655)
>>> Nov 28 11:59:42 rsuk-mhb-fw01 tinc.dcvpn[24911]: Got MTU probe 
>>> length
>>> 1443 from rps (2001:1b40:5000:9::2 port 655)
>>> Nov 28 11:59:43 rsuk-mhb-fw01 tinc.dcvpn[24911]: Sending MTU probe
>>> length 1451 to rps (2001:1b40:5000:9::2 port 655)
>>> Nov 28 11:59:43 rsuk-mhb-fw01 tinc.dcvpn[24911]: Sending MTU probe
>>> length 1443 to rps (2001:1b40:5000:9::2 port 655)
>>> Nov 28 11:59:43 rsuk-mhb-fw01 tinc.dcvpn[24911]: Sending MTU probe
>>> length 1443 to rps (2001:1b40:5000:9::2 port 655)
>>> Nov 28 11:59:43 rsuk-mhb-fw01 tinc.dcvpn[24911]: Sending MTU probe
>>> length 1443 to rps (2001:1b40:5000:9::2 port 655)
>>> Nov 28 11:59:43 rsuk-mhb-fw01 tinc.dcvpn[24911]: Got MTU probe 
>>> length
>>> 1443 from rps (2001:1b40:5000:9::2 port 655)
>>> Nov 28 11:59:43 rsuk-mhb-fw01 tinc.dcvpn[24911]: Got MTU probe 
>>> length
>>> 1443 from rps (2001:1b40:5000:9::2 port 655)
>>> Nov 28 11:59:43 rsuk-mhb-fw01 tinc.dcvpn[24911]: Got MTU probe 
>>> length
>>> 1443 from rps (2001:1b40:5000:9::2 port 655)
>>> Nov 28 11:59:43 rsuk-mhb-fw01 tinc.dcvpn[24911]: Sending packet of
>>> 118 bytes to rps (2001:1b40:5000:9::2 port 655)
>>> Nov 28 11:59:44 rsuk-mhb-fw01 tinc.dcvpn[24911]: Sending packet of
>>> 118 bytes to rps (2001:1b40:5000:9::2 port 655)
>>> Nov 28 11:59:45 rsuk-mhb-fw01 tinc.dcvpn[24911]: Sending packet of
>>> 118 bytes to rps (2001:1b40:5000:9::2 port 655)
>>> Nov 28 11:59:46 rsuk-mhb-fw01 tinc.dcvpn[24911]: Sending packet of
>>> 118 bytes to rps (2001:1b40:5000:9::2 port 655)
>>> Nov 28 11:59:47 rsuk-mhb-fw01 tinc.dcvpn[24911]: Sending packet of
>>> 118 bytes to rps (2001:1b40:5000:9::2 port 655)
>>> Nov 28 11:59:49 rsuk-mhb-fw01 tinc.dcvpn[24911]: Clamping MSS of
>>> packet from rsukmhb to rps to 1369
>>> Nov 28 11:59:49 rsuk-mhb-fw01 tinc.dcvpn[24911]: Sending packet of 
>>> 86
>>> bytes to rps (2001:1b40:5000:9::2 port 655)
>>> Nov 28 11:59:49 rsuk-mhb-fw01 tinc.dcvpn[24911]: Sending packet of 
>>> 74
>>> bytes to rps (2001:1b40:5000:9::2 port 655)
>>> Nov 28 11:59:49 rsuk-mhb-fw01 tinc.dcvpn[24911]: Sending packet of
>>> 224 bytes to rps (2001:1b40:5000:9::2 port 655)
>>> Nov 28 11:59:49 rsuk-mhb-fw01 tinc.dcvpn[24911]: Sending packet of 
>>> 74
>>> bytes to rps (2001:1b40:5000:9::2 port 655)
>>> Nov 28 11:59:49 rsuk-mhb-fw01 tinc.dcvpn[24911]: Sending packet of 
>>> 74
>>> bytes to rps (2001:1b40:5000:9::2 port 655)
>>> Nov 28 11:59:55 rsuk-mhb-fw01 tinc.dcvpn[24911]: Clamping MSS of
>>> packet from rsukmhb to rps to 1369
>>> Nov 28 11:59:55 rsuk-mhb-fw01 tinc.dcvpn[24911]: Sending packet of 
>>> 86
>>> bytes to rps (2001:1b40:5000:9::2 port 655)
>>> Nov 28 11:59:55 rsuk-mhb-fw01 tinc.dcvpn[24911]: Sending packet of
>>> 112 bytes to rps (2001:1b40:5000:9::2 port 655)
>>> Nov 28 11:59:55 rsuk-mhb-fw01 tinc.dcvpn[24911]: Sending packet of 
>>> 74
>>> bytes to rps (2001:1b40:5000:9::2 port 655)
>>> Nov 28 11:59:55 rsuk-mhb-fw01 tinc.dcvpn[24911]: Sending packet of
>>> 106 bytes to rps (2001:1b40:5000:9::2 port 655)
>>> Nov 28 11:59:55 rsuk-mhb-fw01 tinc.dcvpn[24911]: Sending packet of 
>>> 89
>>> bytes to rps (2001:1b40:5000:9::2 port 655)
>>> Nov 28 11:59:55 rsuk-mhb-fw01 tinc.dcvpn[24911]: Sending packet of 
>>> 74
>>> bytes to rps (2001:1b40:5000:9::2 port 655)
>>> Nov 28 11:59:55 rsuk-mhb-fw01 tinc.dcvpn[24911]: Sending packet of 
>>> 74
>>> bytes to rps (2001:1b40:5000:9::2 port 655)
>>> rps site (where rsync server is):
>>> -----------------------------------------
>>> [thomas.parrott at rps-fw03 ~]$ grep '11:59:' /var/log/messages
>>> Nov 28 11:59:01 rps-fw03 tinc.dcvpn[17321]: Clamping MSS of packet
>>> from rps to rsukmhb to 1369
>>> Nov 28 11:59:01 rps-fw03 tinc.dcvpn[17321]: Sending packet of 86
>>> bytes to rsukmhb (2001:1b40:5000:19::2 port 655)
>>> Nov 28 11:59:01 rps-fw03 tinc.dcvpn[17321]: Sending packet of 74
>>> bytes to rsukmhb (2001:1b40:5000:19::2 port 655)
>>> Nov 28 11:59:01 rps-fw03 tinc.dcvpn[17321]: Sending packet of 433
>>> bytes to rsukmhb (2001:1b40:5000:19::2 port 655)
>>> Nov 28 11:59:01 rps-fw03 tinc.dcvpn[17321]: Sending packet of 74
>>> bytes to rsukmhb (2001:1b40:5000:19::2 port 655)
>>> Nov 28 11:59:01 rps-fw03 tinc.dcvpn[17321]: Sending packet of 74
>>> bytes to rsukmhb (2001:1b40:5000:19::2 port 655)
>>> Nov 28 11:59:01 rps-fw03 tinc.dcvpn[17321]: Clamping MSS of packet
>>> from rps to rsukmhb to 1369
>>> Nov 28 11:59:01 rps-fw03 tinc.dcvpn[17321]: Sending packet of 86
>>> bytes to rsukmhb (2001:1b40:5000:19::2 port 655)
>>> Nov 28 11:59:01 rps-fw03 tinc.dcvpn[17321]: Sending packet of 74
>>> bytes to rsukmhb (2001:1b40:5000:19::2 port 655)
>>> Nov 28 11:59:01 rps-fw03 tinc.dcvpn[17321]: Sending packet of 88
>>> bytes to rsukmhb (2001:1b40:5000:19::2 port 655)
>>> Nov 28 11:59:01 rps-fw03 tinc.dcvpn[17321]: Sending packet of 115
>>> bytes to rsukmhb (2001:1b40:5000:19::2 port 655)
>>> Nov 28 11:59:01 rps-fw03 tinc.dcvpn[17321]: Sending packet of 86
>>> bytes to rsukmhb (2001:1b40:5000:19::2 port 655)
>>> Nov 28 11:59:01 rps-fw03 tinc.dcvpn[17321]: Sending packet of 74
>>> bytes to rsukmhb (2001:1b40:5000:19::2 port 655)
>>> Nov 28 11:59:01 rps-fw03 tinc.dcvpn[17321]: Sending packet of 74
>>> bytes to rsukmhb (2001:1b40:5000:19::2 port 655)
>>> Nov 28 11:59:01 rps-fw03 tinc.dcvpn[17321]: Sending packet of 75
>>> bytes to rsukmhb (2001:1b40:5000:19::2 port 655)
>>> Nov 28 11:59:02 rps-fw03 tinc.dcvpn[17321]: Sending packet of 78
>>> bytes to rsukmhb (2001:1b40:5000:19::2 port 655)
>>> Nov 28 11:59:02 rps-fw03 tinc.dcvpn[17321]: Sending packet of 78
>>> bytes to rsukmhb (2001:1b40:5000:19::2 port 655)
>>> Nov 28 11:59:02 rps-fw03 tinc.dcvpn[17321]: Sending packet of 1443
>>> bytes to rsukmhb (2001:1b40:5000:19::2 port 655)
>>> Nov 28 11:59:02 rps-fw03 tinc.dcvpn[17321]: Sending packet of 1443
>>> bytes to rsukmhb (2001:1b40:5000:19::2 port 655)
>>> Nov 28 11:59:02 rps-fw03 tinc.dcvpn[17321]: Sending packet of 1443
>>> bytes to rsukmhb (2001:1b40:5000:19::2 port 655)
>>> Nov 28 11:59:02 rps-fw03 tinc.dcvpn[17321]: Sending packet of 1443
>>> bytes to rsukmhb (2001:1b40:5000:19::2 port 655)
>>> Nov 28 11:59:02 rps-fw03 tinc.dcvpn[17321]: Sending packet of 1443
>>> bytes to rsukmhb (2001:1b40:5000:19::2 port 655)
>>> Nov 28 11:59:02 rps-fw03 tinc.dcvpn[17321]: Sending packet of 1417
>>> bytes to rsukmhb (2001:1b40:5000:19::2 port 655)
>>> Nov 28 11:59:02 rps-fw03 tinc.dcvpn[17321]: Sending packet of 1443
>>> bytes to rsukmhb (2001:1b40:5000:19::2 port 655)
>>> Nov 28 11:59:02 rps-fw03 tinc.dcvpn[17321]: Sending packet of 1443
>>> bytes to rsukmhb (2001:1b40:5000:19::2 port 655)
>>> Nov 28 11:59:02 rps-fw03 tinc.dcvpn[17321]: Sending packet of 1443
>>> bytes to rsukmhb (2001:1b40:5000:19::2 port 655)
>>> Nov 28 11:59:02 rps-fw03 tinc.dcvpn[17321]: Sending packet of 1443
>>> bytes to rsukmhb (2001:1b40:5000:19::2 port 655)
>>> Nov 28 11:59:02 rps-fw03 tinc.dcvpn[17321]: Sending packet of 1443
>>> bytes to rsukmhb (2001:1b40:5000:19::2 port 655)
>>> Nov 28 11:59:02 rps-fw03 tinc.dcvpn[17321]: Sending packet of 1443
>>> bytes to rsukmhb (2001:1b40:5000:19::2 port 655)
>>> Nov 28 11:59:02 rps-fw03 tinc.dcvpn[17321]: Sending packet of 1035
>>> bytes to rsukmhb (2001:1b40:5000:19::2 port 655)
>>> Nov 28 11:59:02 rps-fw03 tinc.dcvpn[17321]: Sending packet of 74
>>> bytes to rsukmhb (2001:1b40:5000:19::2 port 655)
>>> Nov 28 11:59:02 rps-fw03 tinc.dcvpn[17321]: Sending packet of 89
>>> bytes to rsukmhb (2001:1b40:5000:19::2 port 655)
>>> Nov 28 11:59:02 rps-fw03 tinc.dcvpn[17321]: Sending packet of 89
>>> bytes to rsukmhb (2001:1b40:5000:19::2 port 655)
>>> Nov 28 11:59:02 rps-fw03 tinc.dcvpn[17321]: Sending packet of 79
>>> bytes to rsukmhb (2001:1b40:5000:19::2 port 655)
>>> Nov 28 11:59:02 rps-fw03 tinc.dcvpn[17321]: Sending packet of 98
>>> bytes to rsukmhb (2001:1b40:5000:19::2 port 655)
>>> Nov 28 11:59:02 rps-fw03 tinc.dcvpn[17321]: Sending packet of 74
>>> bytes to rsukmhb (2001:1b40:5000:19::2 port 655)
>>> Nov 28 11:59:02 rps-fw03 tinc.dcvpn[17321]: Sending packet of 74
>>> bytes to rsukmhb (2001:1b40:5000:19::2 port 655)
>>> Nov 28 11:59:03 rps-fw03 tinc.dcvpn[17321]: Sending packet of 107
>>> bytes to rsukmhb (2001:1b40:5000:19::2 port 655)
>>> Nov 28 11:59:10 rps-fw03 tinc.dcvpn[17321]: Sending packet of 118
>>> bytes to rsukmhb (2001:1b40:5000:19::2 port 655)
>>> Nov 28 11:59:11 rps-fw03 tinc.dcvpn[17321]: Sending packet of 118
>>> bytes to rsukmhb (2001:1b40:5000:19::2 port 655)
>>> Nov 28 11:59:11 rps-fw03 tinc.dcvpn[17321]: Clamping MSS of packet
>>> from rps to rsukmhb to 1369
>>> Nov 28 11:59:11 rps-fw03 tinc.dcvpn[17321]: Sending packet of 86
>>> bytes to rsukmhb (2001:1b40:5000:19::2 port 655)
>>> Nov 28 11:59:11 rps-fw03 tinc.dcvpn[17321]: Sending packet of 74
>>> bytes to rsukmhb (2001:1b40:5000:19::2 port 655)
>>> Nov 28 11:59:11 rps-fw03 tinc.dcvpn[17321]: Sending packet of 433
>>> bytes to rsukmhb (2001:1b40:5000:19::2 port 655)
>>> Nov 28 11:59:11 rps-fw03 tinc.dcvpn[17321]: Sending packet of 74
>>> bytes to rsukmhb (2001:1b40:5000:19::2 port 655)
>>> Nov 28 11:59:11 rps-fw03 tinc.dcvpn[17321]: Sending packet of 74
>>> bytes to rsukmhb (2001:1b40:5000:19::2 port 655)
>>> Nov 28 11:59:12 rps-fw03 tinc.dcvpn[17321]: Sending packet of 118
>>> bytes to rsukmhb (2001:1b40:5000:19::2 port 655)
>>> Nov 28 11:59:13 rps-fw03 tinc.dcvpn[17321]: Sending packet of 118
>>> bytes to rsukmhb (2001:1b40:5000:19::2 port 655)
>>> Nov 28 11:59:14 rps-fw03 tinc.dcvpn[17321]: Sending packet of 118
>>> bytes to rsukmhb (2001:1b40:5000:19::2 port 655)
>>> Nov 28 11:59:21 rps-fw03 tinc.dcvpn[17321]: Clamping MSS of packet
>>> from rps to rsukmhb to 1369
>>> Nov 28 11:59:21 rps-fw03 tinc.dcvpn[17321]: Sending packet of 86
>>> bytes to rsukmhb (2001:1b40:5000:19::2 port 655)
>>> Nov 28 11:59:21 rps-fw03 tinc.dcvpn[17321]: Sending packet of 74
>>> bytes to rsukmhb (2001:1b40:5000:19::2 port 655)
>>> Nov 28 11:59:21 rps-fw03 tinc.dcvpn[17321]: Sending packet of 433
>>> bytes to rsukmhb (2001:1b40:5000:19::2 port 655)
>>> Nov 28 11:59:21 rps-fw03 tinc.dcvpn[17321]: Sending packet of 74
>>> bytes to rsukmhb (2001:1b40:5000:19::2 port 655)
>>> Nov 28 11:59:21 rps-fw03 tinc.dcvpn[17321]: Sending packet of 74
>>> bytes to rsukmhb (2001:1b40:5000:19::2 port 655)
>>> Nov 28 11:59:29 rps-fw03 tinc.dcvpn[17321]: Clamping MSS of packet
>>> from rps to rsukmhb to 1369
>>> Nov 28 11:59:29 rps-fw03 tinc.dcvpn[17321]: Sending packet of 86
>>> bytes to rsukmhb (2001:1b40:5000:19::2 port 655)
>>> Nov 28 11:59:29 rps-fw03 tinc.dcvpn[17321]: Sending packet of 74
>>> bytes to rsukmhb (2001:1b40:5000:19::2 port 655)
>>> Nov 28 11:59:29 rps-fw03 tinc.dcvpn[17321]: Sending packet of 433
>>> bytes to rsukmhb (2001:1b40:5000:19::2 port 655)
>>> Nov 28 11:59:29 rps-fw03 tinc.dcvpn[17321]: Sending packet of 74
>>> bytes to rsukmhb (2001:1b40:5000:19::2 port 655)
>>> Nov 28 11:59:29 rps-fw03 tinc.dcvpn[17321]: Sending packet of 74
>>> bytes to rsukmhb (2001:1b40:5000:19::2 port 655)
>>> Nov 28 11:59:34 rps-fw03 tinc.dcvpn[17321]: Sending packet of 122
>>> bytes to rsukmhb (2001:1b40:5000:19::2 port 655)
>>> Nov 28 11:59:39 rps-fw03 tinc.dcvpn[17321]: Clamping MSS of packet
>>> from rps to rsukmhb to 1369
>>> Nov 28 11:59:39 rps-fw03 tinc.dcvpn[17321]: Sending packet of 86
>>> bytes to rsukmhb (2001:1b40:5000:19::2 port 655)
>>> Nov 28 11:59:39 rps-fw03 tinc.dcvpn[17321]: Sending packet of 74
>>> bytes to rsukmhb (2001:1b40:5000:19::2 port 655)
>>> Nov 28 11:59:39 rps-fw03 tinc.dcvpn[17321]: Sending packet of 433
>>> bytes to rsukmhb (2001:1b40:5000:19::2 port 655)
>>> Nov 28 11:59:39 rps-fw03 tinc.dcvpn[17321]: Sending packet of 74
>>> bytes to rsukmhb (2001:1b40:5000:19::2 port 655)
>>> Nov 28 11:59:39 rps-fw03 tinc.dcvpn[17321]: Sending packet of 74
>>> bytes to rsukmhb (2001:1b40:5000:19::2 port 655)
>>> Nov 28 11:59:42 rps-fw03 tinc.dcvpn[17321]: Sending MTU probe length
>>> 1451 to rsukmhb (2001:1b40:5000:19::2 port 655)
>>> Nov 28 11:59:42 rps-fw03 tinc.dcvpn[17321]: Sending MTU probe length
>>> 1443 to rsukmhb (2001:1b40:5000:19::2 port 655)
>>> Nov 28 11:59:42 rps-fw03 tinc.dcvpn[17321]: Sending MTU probe length
>>> 1443 to rsukmhb (2001:1b40:5000:19::2 port 655)
>>> Nov 28 11:59:42 rps-fw03 tinc.dcvpn[17321]: Sending MTU probe length
>>> 1443 to rsukmhb (2001:1b40:5000:19::2 port 655)
>>> Nov 28 11:59:42 rps-fw03 tinc.dcvpn[17321]: Got MTU probe length 
>>> 1443
>>> from rsukmhb (2001:1b40:5000:19::2 port 655)
>>> Nov 28 11:59:42 rps-fw03 tinc.dcvpn[17321]: Got MTU probe length 
>>> 1443
>>> from rsukmhb (2001:1b40:5000:19::2 port 655)
>>> Nov 28 11:59:42 rps-fw03 tinc.dcvpn[17321]: Got MTU probe length 
>>> 1443
>>> from rsukmhb (2001:1b40:5000:19::2 port 655)
>>> Nov 28 11:59:43 rps-fw03 tinc.dcvpn[17321]: Got MTU probe length 
>>> 1443
>>> from rsukmhb (2001:1b40:5000:19::2 port 655)
>>> Nov 28 11:59:43 rps-fw03 tinc.dcvpn[17321]: Got MTU probe length 
>>> 1443
>>> from rsukmhb (2001:1b40:5000:19::2 port 655)
>>> Nov 28 11:59:43 rps-fw03 tinc.dcvpn[17321]: Got MTU probe length 
>>> 1443
>>> from rsukmhb (2001:1b40:5000:19::2 port 655)
>>> Nov 28 11:59:43 rps-fw03 tinc.dcvpn[17321]: Sending packet of 118
>>> bytes to rsukmhb (2001:1b40:5000:19::2 port 655)
>>> Nov 28 11:59:44 rps-fw03 tinc.dcvpn[17321]: Sending packet of 118
>>> bytes to rsukmhb (2001:1b40:5000:19::2 port 655)
>>> Nov 28 11:59:45 rps-fw03 tinc.dcvpn[17321]: Sending packet of 118
>>> bytes to rsukmhb (2001:1b40:5000:19::2 port 655)
>>> Nov 28 11:59:46 rps-fw03 tinc.dcvpn[17321]: Sending packet of 118
>>> bytes to rsukmhb (2001:1b40:5000:19::2 port 655)
>>> Nov 28 11:59:47 rps-fw03 tinc.dcvpn[17321]: Sending packet of 118
>>> bytes to rsukmhb (2001:1b40:5000:19::2 port 655)
>>> Nov 28 11:59:49 rps-fw03 tinc.dcvpn[17321]: Clamping MSS of packet
>>> from rps to rsukmhb to 1369
>>> Nov 28 11:59:49 rps-fw03 tinc.dcvpn[17321]: Sending packet of 86
>>> bytes to rsukmhb (2001:1b40:5000:19::2 port 655)
>>> Nov 28 11:59:49 rps-fw03 tinc.dcvpn[17321]: Sending packet of 74
>>> bytes to rsukmhb (2001:1b40:5000:19::2 port 655)
>>> Nov 28 11:59:49 rps-fw03 tinc.dcvpn[17321]: Sending packet of 433
>>> bytes to rsukmhb (2001:1b40:5000:19::2 port 655)
>>> Nov 28 11:59:49 rps-fw03 tinc.dcvpn[17321]: Sending packet of 74
>>> bytes to rsukmhb (2001:1b40:5000:19::2 port 655)
>>> Nov 28 11:59:49 rps-fw03 tinc.dcvpn[17321]: Sending packet of 74
>>> bytes to rsukmhb (2001:1b40:5000:19::2 port 655)
>>> Nov 28 11:59:55 rps-fw03 tinc.dcvpn[17321]: Clamping MSS of packet
>>> from rps to rsukmhb to 1369
>>> Nov 28 11:59:55 rps-fw03 tinc.dcvpn[17321]: Sending packet of 86
>>> bytes to rsukmhb (2001:1b40:5000:19::2 port 655)
>>> Nov 28 11:59:55 rps-fw03 tinc.dcvpn[17321]: Sending packet of 74
>>> bytes to rsukmhb (2001:1b40:5000:19::2 port 655)
>>> Nov 28 11:59:55 rps-fw03 tinc.dcvpn[17321]: Sending packet of 74
>>> bytes to rsukmhb (2001:1b40:5000:19::2 port 655)
>>> Nov 28 11:59:55 rps-fw03 tinc.dcvpn[17321]: Sending packet of 105
>>> bytes to rsukmhb (2001:1b40:5000:19::2 port 655)
>>> Nov 28 11:59:55 rps-fw03 tinc.dcvpn[17321]: Sending packet of 80
>>> bytes to rsukmhb (2001:1b40:5000:19::2 port 655)
>>> Nov 28 11:59:55 rps-fw03 tinc.dcvpn[17321]: Sending packet of 74
>>> bytes to rsukmhb (2001:1b40:5000:19::2 port 655)
>>> Nov 28 11:59:55 rps-fw03 tinc.dcvpn[17321]: Sending packet of 74
>>> bytes to rsukmhb (2001:1b40:5000:19::2 port 655)
>>> Neither firewalls are heaving loaded.
>>> Thanks
>>> Tom
>>> On 2013-11-28 11:49, tomp at Tomp.co.uk wrote:
>>>> Hi,
>>>> I am using tinc 1.0.23 in router mode and am having trouble with
>>>> intermittent TCP connect timeouts that do not occur when routing 
>>>> the
>>>> TCP over the internet directly.
>>>> I am using a pure IPv6 setup (i.e direct IPv6 connections, and
>>>> tunneled IPv6 subnets).
>>>> My configs are as follows:
>>>> Site 1:
>>>> -----------------------
>>>> tinc.conf:
>>>> Name = rsukmhb
>>>> AddressFamily = ipv6
>>>> BindToAddress = 2001:1b40:5000:19::2
>>>> ConnectTo = rps
>>>> IffOneQueue = yes
>>>> tinc-up:
>>>> #!/bin/sh
>>>> logger -t tinc Bringing up interface $INTERFACE
>>>> ip -6 link set "$INTERFACE" up
>>>> ip -6 link set "$INTERFACE" txqueuelen 10
>>>> ip -6 addr add fdd1:c52a:3c24:3384::2/64 dev "$INTERFACE"
>>>> subnet-up:
>>>> #!/bin/sh
>>>> [ -z "$NAME" ] && exit 0
>>>> [ "$NAME" = "$NODE" ] && exit 0
>>>> logger -t tinc Adding route to $SUBNET for $NODE on $NAME
>>>> ip -6 route replace $SUBNET dev $INTERFACE
>>>> Site 2:
>>>> -----------------------
>>>> tinc.conf:
>>>> Name = rps
>>>> AddressFamily = ipv6
>>>> BindToAddress = 2001:1b40:5000:9::2
>>>> ConnectTo = rsukmhb
>>>> IffOneQueue = yes
>>>> tinc-up:
>>>> #!/bin/sh
>>>> logger -t tinc Bringing up interface $INTERFACE
>>>> ip -6 link set "$INTERFACE" up
>>>> ip -6 link set "$INTERFACE" txqueuelen 10
>>>> ip -6 addr add fdd1:c52a:3c24:3384::1/64 dev "$INTERFACE
>>>> subnet-up:
>>>> #!/bin/sh
>>>> [ -z "$NAME" ] && exit 0
>>>> [ "$NAME" = "$NODE" ] && exit 0
>>>> logger -t tinc Adding route to $SUBNET for $NODE on $NAME
>>>> ip -6 route replace $SUBNET dev $INTERFACE
>>>> The VPN tun interfaces use private IPv6 IP addresses in the
>>>> fdd1:c52a:3c24:3384::/64 range.
>>>> I am then using the host entries at each site to advertise an IPv6
>>>> /64 subnet used internally (although still publically routable 
>>>> address
>>>> subnet) so that it is routed over the VPN tunnel to the other side.
>>>> This is working pretty well and I am getting around 80MBits/sec 
>>>> throughput.
>>>> However we have an cron process that runs every 1 minute and makes
>>>> several HTTP requests over the VPN every 10s.
>>>> About 10-12 times a day we are getting these errors after the
>>>> specified 5 second connect timeout set in the app.
>>>> Request failed: connect() timed out!
>>>> If we disable the VPN and just route the requests over the internet
>>>> (as I said they are publically routable addresses) then we do not 
>>>> see
>>>> these errors, suggesting this is not an application problem.
>>>> We are also running Cacti and Nagios over the VPN for monitoring 
>>>> the
>>>> remote site.
>>>> The traffic level is low, averaging about 20 kbps, but quiet 
>>>> bursty,
>>>> as every few minutes nagios/cacti runs, and the rest of the time 
>>>> the
>>>> tunnel is quiet except for this cron app that makes a very small 
>>>> HTTP
>>>> request every 10s.
>>>> Do you know what I could be looking at to fix this?
>>>> I have found these posts that suggest a similar connect() timeout 
>>>> issue:
>>>> Page 12 of this doc:
>>>> http://tinc-vpn.org/presentations/fosdem-2011/ec2_vpn_fosdem2011.pdf
>>>> http://thr3ads.net/tinc-devel/2010/10/1964008-Tweaks-for-high-bandwidth-tinc
>>>> I have tried disabled replay protection, setting IffOneQueue,
>>>> lowering and increasing the txqueuelen, setting priority of the 
>>>> tinc
>>>> process.
>>>> None of these settings have improved things though.
>>>> Any thoughts would be much appreciated.
>>>> Thanks
>>>> Tom