Re: [mailop] Anyone from Yahoo - icmpv6 filtering breaks login.yahoo.com MTU detection

2016-11-21 Thread Franck Martin via mailop
It is also common when people convert their ACL from IPv4 to IPv6 to forget to add a rule of PTB in their IPv6 ACLs... I would also suggest to use tracepath(6) for debugging, as it factors the port you want to reach and will try to detect the pmtu. You may find where the packet gets dropped this w

[mailop] Cisco / SenderBase support filtering

2016-11-21 Thread Michael Orlitzky
> : host vmx.sco.cisco.com[184.94.241.135] refused to > talk to me: 554-vmx.sco.cisco.com 554 Your access to this mail system has > been rejected due to the sending MTA's poor reputation. If you believe > that > this failure is in error, please contact the intended recipient via >

Re: [mailop] Anyone from Yahoo - icmpv6 filtering breaks login.yahoo.com MTU detection

2016-11-21 Thread Vladimir Dubrovin via mailop
This problem is neither new nor specific to Yahoo or IPv6 and is usually referred as "blackhole router". ICMPv4 "Fragmentation Needed" (type 3 code4) / ICMPv6 "Packet to Big" (type 2) *are required* for path MTU discovery and should never be filtered. The only reason it doesn't strike you with dif