On 20 May 2015, at 16:02, Brian E Carpenter wrote:
On 21/05/2015 03:49, Nico Williams wrote:
On Tue, May 19, 2015 at 09:17:37PM -0600, Doug Royer wrote:
On 05/19/2015 06:49 PM, Christopher Morrow wrote:
sure, v6 works. if you see connect but hang I'd suspect pmtu
problems (at first guess).
Don't understand why yet. By moving the MTU from 1500 (the default
value) to 1420, it works.
Make sure ICMP isn't getting filtered.
Or fragments being dropped.
https://tools.ietf.org/html/draft-ietf-v6ops-ipv6-ehs-in-real-world
Or MSS negotiation failing.
Yeah.
At the risk of stating the obvious, lowering your MTU and declaring the
problem fixed is like fixing a broken window by sticking a poster over
it. The window is still broken, even if the immediate signs that there
is a problem to fix have gone away.
Path MTU discovery being broken is endemic in the v4 network, mainly I
think because of the common wisdom in enterprise networks that ICMP is a
security! risk! and must! be! blocked! The fact that these kinds of
problems persist in v6 is perhaps a sign that enterprises are deploying
it? Trying hard to see the glass as half full, here. :-)
Joe