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Date:      Wed, 26 Jun 2019 10:05:05 +0200
From:      "Patrick M. Hausen" <hausen@punkt.de>
To:        FreeBSD Net <freebsd-net@freebsd.org>
Cc:        mops@punkt.de
Subject:   IPFW NAT64 changed 11.2 --> 11.3?
Message-ID:  <950200A8-6D36-46FE-B0DD-BA6EA860FEB7@punkt.de>

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Hi all,

we have a bit of a problem with some new servers that
use NAT64 to access certain services that offer only
legacy IP - like github.

As far as I found the respective NAT64 gateways (in jails
with VNET) are configured identically except for the
particular addresses, of course.

Yet, 11.2 works, 11.3-RC1 doesn=E2=80=99t.

OK, on to the config =E2=80=A6

Working server:

ifconfig inet0
inet0: flags=3D8843<UP,BROADCAST,RUNNING,SIMPLEX,MULTICAST> metric 0 mtu =
1500
	inet6 2a00:b580:8000:12:xxxx:xxxx:xxxx:xxxx prefixlen 64

netstat -rn
64:ff9b::/96                      2a00:b580:8000:12:yyyy:yyyy:yyyy:yyyy =
UGS    inet0

drill github.map.fastly.net aaaa
github.map.fastly.net.	15	IN	AAAA	64:ff9b::9765:7085

ping6 github.map.fastly.net=20
16 bytes from 64:ff9b::9765:7085, icmp_seq=3D0 hlim=3D57 time=3D3.801 ms


Broken server:

ifconfig inet0
inet0: flags=3D8843<UP,BROADCAST,RUNNING,SIMPLEX,MULTICAST> metric 0 mtu =
1500
	inet6 2a00:b580:8000:12:xxxx:xxxx:xxxx:xxxx prefixlen 64

netstat -rn
64:ff9b::/96                      2a00:b580:8000:12:yyyy:yyyy:yyyy:yyyy =
UGS    inet0

drill github.map.fastly.net aaaa
github.map.fastly.net.	15	IN	AAAA	64:ff9b::9765:7085

So up to the 4-in-6 DNS translation everything is working as it should, =
but then
when actual traffic is involved:

ping6 github.map.fastly.net
16 bytes from d91d:2891::9765:7085, icmp_seq=3D0 hlim=3D57 time=3D2.324 =
ms

What the =E2=80=A6 is this IP address here? All I know is that the block =
is supposed to be
IANA reserved. And TCP connections to github.map.fastly.net of course =
stall, never
receiving an answer packet.

The NAT64 gateways on both servers have these ipfw rules:

root@gate64:~ # ipfw list
00100 allow ip from any to any via lo0
00200 deny ip from any to 127.0.0.0/8
00300 deny ip from 127.0.0.0/8 to any
00400 deny ip from any to ::1
00500 deny ip from ::1 to any
01100 allow ipv6-icmp from :: to ff02::/16
01200 allow ipv6-icmp from fe80::/10 to fe80::/10
01300 allow ipv6-icmp from fe80::/10 to ff02::/16
01400 allow ipv6-icmp from any to me6 ip6 icmp6types 1,2,3,4
01500 allow ipv6-icmp from any to any ip6 icmp6types 135,136
02000 allow icmp from any to me icmptypes 8
02100 allow ipv6-icmp from any to me6 ip6 icmp6types 128,129
03000 allow tcp from any to 217.29.40.y 80,443
03100 allow tcp from me6 to any 80,443
05000 nat64lsn NAT64 ip from 2a00:b580::/32 to 64:ff9b::/96 in
05100 nat64lsn NAT64 ip from any to 217.29.40.y in
65535 allow ip from any to any

Any hints welcome.

Thanks,
Patrick
--=20
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