pay.gov and IPv6

Mon Nov 21 00:26:34 UTC 2016

In message <1479686835.13553.4.camel at ns.five-ten-sg.com>, Carl Byington writes:
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> On Sun, 2016-11-20 at 10:51 +0100, JORDI PALET MARTINEZ wrote:
> > For example, you will not get this working if you have a lower MTU
> > than 1.500, which is quite normal, not just for tunnels, but also
> > because the PPP/others encapsulation in many access links:
> 
> > http://diskmakerx.com/
> 
> curl -6 -v http://diskmakerx.com/
> 
> That works here via an he.net tunnel. Perhaps 1and1 fixed something.

And the advertised MSS was what?  On my box I'm seeing 1220 for
IPv6 compared with 1460 for IPv4.  1220 shouldn't see PMTU problems.

1460 on the other hand will cause problems as more clients are
forced behind IPv4 as a service links.

11:14:50.056215 IP 172.30.42.121.52280 > 217.160.0.214.80: Flags [S], seq 2115844511, win 65535, options [mss 1460,nop,wscale 4,nop,nop,TS val 538455715 ecr 0,sackOK,eol], length 0
11:14:50.137770 IP6 2001:470:a001:4:c00d:3d8c:14e7:6de3.52282 > 2001:8d8:100f:f000::2d5.80: Flags [S], seq 4181372812, win 65535, options [mss 1220,nop,wscale 4,nop,nop,TS val 538455793 ecr 0,sackOK,eol], length 0

Mark

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-- 
Mark Andrews, ISC
1 Seymour St., Dundas Valley, NSW 2117, Australia
PHONE: +61 2 9871 4742                 INTERNET: marka at isc.org