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Date: Sat, 30 Nov 2013 01:30:10 -0800 (PST)
From: Monkey <crapsh@monkeybrains.net>
Reply-To: Monkey <crapsh@monkeybrains.net>
To: FreeBSD-gnats-submit@freebsd.org
Cc:
Subject: libalias fails to adjust MTU from jails
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>Number:         184389
>Category:       kern
>Synopsis:       [libalias] libalias fails to adjust MTU from jails
>Confidential:   no
>Severity:       non-critical
>Priority:       medium
>Responsible:    freebsd-net
>State:          open
>Quarter:        
>Keywords:       
>Date-Required:  
>Class:          sw-bug
>Submitter-Id:   current-users
>Arrival-Date:   Sat Nov 30 10:00:00 UTC 2013
>Closed-Date:    
>Last-Modified:  Sun May 04 05:15:23 UTC 2014
>Originator:     Monkey
>Release:        FreeBSD 9.2-RELEASE-p2 amd64
>Organization:
MonkeyBrains.net
>Environment:
System: FreeBSD papadum 9.2-RELEASE-p2 FreeBSD 9.2-RELEASE-p2 #0: Sat Nov 30 00:46:30 PST 2013 monkey@papadum:/usr/obj/usr/src/sys/GENERIC amd64


	ipfw_nat, libalias
>Description:
	MTU size is not properly discovered from packets generated from jails.  libalias and/or ipfw_nat
	need to communicate with the network stack to determine MTU.
>How-To-Repeat:
	Set up ipfw_nat to nat packets generated from a jail.
	Send those packets to a second FreeBSD box that has a GRE tunnel to third machine.
	Attempt to ssh or scp a file larger than 1500 bytes from the jail to the third machine -- it hangs.
	If you SSH from the host (outside of the jail), the ssh connects.
	If you quickly log into the jail, it will briefly work (OS remembers MTU size for that path).
>Fix:
	Set the MTU to 1476 on the interface connecting computer A to computer B.

>Release-Note:
>Audit-Trail:
Responsible-Changed-From-To: freebsd-bugs->freebsd-net 
Responsible-Changed-By: linimon 
Responsible-Changed-When: Sun May 4 05:14:51 UTC 2014 
Responsible-Changed-Why:  
Over to maintainer(s). 

http://www.freebsd.org/cgi/query-pr.cgi?pr=184389 
>Unformatted:
