and IPv6

Carl Byington carl at
Fri Nov 18 18:22:53 UTC 2016

> > I am working with at, trying to explain the
> problem.

The intersection of government bureaucracy and technical issues is
frustrating to say the least. I just sent the message below, but have no
expectation that it will change anything. 


On Fri, 2016-11-18 at 12:39 +0000, CLEV Pay Gov wrote:
> It would be best to discuss this via phone.  Please contact our help
> desk at the number below and we could see if there's anything we could
> do over the phone to help troubleshoot.

That is hopeless. Verbal technical discussions rarely work unless both
sides can see the same text. Have you ever tried (while talking on the
phone) to get someone to type in without making a bunch of
mistakes in the spelling??

Anyway, just for my amusement, I did call 800-624-1373, Option #2, and
am on the line now, trying to explain this. 10 minutes and counting. Ok,
there does not seem to be any overall ticket for " does not work
at all". They refuse to open a tech support ticket.

> If not, we may need to open a ticket for our technical support.

Please open a ticket, and attach the following text for your tech
support folks. Alternatively, have them look at the " and ipv6"
thread on nanog: has an IPv6 address of 2605:3100:fffd:100::15, but that
machine or its upstream routers are filtering icmpv6 messages. That web
site is not accessible from systems with an MTU of 1280 bytes.

The test case is:

echo -e 'GET /public/home HTTP/1.0\n' | \
openssl s_client -servername -ign_eof -connect \

Run that (or just use a browser to try from a
system with a 1500 byte MTU, and it works. Run it from a system with
upstream connectivity via a tunnel, so the path MTU is smaller, and it
fails. Such tunnels are common for IPv6.

Please stop filtering icmpv6.

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