[SOLVED] 12.2-STABLE: Commit 367740 breaks IMAP/SMTP server authentication

[Michael Grimm]

Hi,

I finally managed to solve this issue: the MTU of all bridged network interfaces had to be reduced from 1500 down to 1490. (The external interface was on 1490 already.)

I still don't understand why these patches of commit 367740 could cause this, and I do not have the knowledge to understand it.

Anyway, I just wanted to let you know.

Regards,
Michael


> On 22. Nov 2020, at 14:37, Michael Grimm <trashcan at ellael.org> wrote:
> 
> Hi,
> 
> I am running 12.2-STABLE and VNET jails, one of which host a recent Dovecot IMAP and a recent postfix SMTP server. Authentication is forced via TLS/SSL for both services (ports 587 and 993). Setup is as follows:
> 
> 	extIF0/pf/NAT <—> epairXa (bridge0) epairXb <-> jail
> 
> A recent upgrade broke mailing of IMAP clients running at macOS 10.14.6 (Mojave) und AVM's push service (Fritzbox), but *not* for IMAP clients running at macOS 10.15.7 (Catalina). Strange.
> 
> Findings at macOS 10.14.6 (examplified for IMAP):
> 
> 1) 	mac$ nc -4vw 1 mail.xyz.zzz 993
> 	found 0 associations
> 	found 1 connections:
> 	    1:	flags=82<CONNECTED,PREFERRED>
> 		outif en0
> 		src 1.2.3.4 port 49583
> 		dst 11.22.33.44 port 993
> 		rank info not available
> 		TCP aux info available
> 
> 	Connection to mail.xyz.zzz port 993 [tcp/imaps] succeeded!
> 
> 2)	mac$ openssl s_client -crlf -connect mail.xyz.zzz:993 -debug
> 	CONNECTED(00000005)
> 	write to 0x7fa32ef01ae0 [0x7fa33080a803] (200 bytes => 200 (0xC8))
> 	0000 - 16 03 01 00 c3 01 00 00-bf 03 03 32 f7 fe fa b4 ...........2.... 
> 	0010 - e8 9a 60 38 ef 34 99 70-84 ce dc 1a 08 b8 76 90   ..`8.4.p……v.
> 	0020 - 19 8c 81 f4 a6 37 19 37-09 70 6f 00 00 60 c0 30   .....7.7.po..`.0
> 	0030 - c0 2c c0 28 c0 24 c0 14-c0 0a 00 9f 00 6b 00 39   .,.(.$.......k.9
> 	0040 - cc a9 cc a8 cc aa ff 85-00 c4 00 88 00 81 00 9d   …………….
> 	0050 - 00 3d 00 35 00 c0 00 84-c0 2f c0 2b c0 27 c0 23   .=.5...../.+.'.#
> 	0060 - c0 13 c0 09 00 9e 00 67-00 33 00 be 00 45 00 9c   .......g.3...E..
> 	0070 - 00 3c 00 2f 00 ba 00 41-c0 11 c0 07 00 05 00 04   .<./...A……..
> 	0080 - c0 12 c0 08 00 16 00 0a-00 15 00 09 00 ff 01 00   …………….
> 	0090 - 00 36 00 0b 00 02 01 00-00 0a 00 08 00 06 00 1d   .6…………..
> 	00a0 - 00 17 00 18 00 23 00 00-00 0d 00 1c 00 1a 06 01   .....#……….
> 	00b0 - 06 03 ef ef 05 01 05 03-04 01 04 03 ee ee ed ed   …………….
> 	00c0 - 03 01 03 03 02 01 02 03-                          ........
> 
> 	hanging at that stage forever 
> 	(and client complaining of its inability to authenticate and reports timeout after 60 seconds)
> 
> 
> I did identify commit 367740 being responsible for that:
> 
> 	mike>	svn up -r 367740
> 	Updating '.':
> 	U    sys/netinet/ip_fastfwd.c
> 	U    sys/netinet/ip_input.c
> 	U    sys/netinet/ip_var.h
> 	 U   .
> 	Updated to revision 367740.
> 
> 
> Any Ideas, especially why clients at different OS behave different?
> 
> FYI: I do have no access to AVM's push service, and very limited access to the macOS 10.14.6 computer.
> 
> Thanks in advance and with kind regards,
> Michael
> 
> P.S. How may I update a local svn copy and simultaneously omit commit 367740 from being applied, or how may I revert commit 367740, only?
> 
> 
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