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Message-Id: <200512051608.jB5G8reQ085129@www.freebsd.org>
Date: Mon, 5 Dec 2005 16:08:53 GMT
From: Frederico Boechat <fboechat@yahoo.com>
To: freebsd-gnats-submit@FreeBSD.org
Subject: PPPoE server permit two clients with the same ip address
X-Send-Pr-Version: www-2.3

>Number:         89979
>Category:       bin
>Synopsis:       [ppp] PPPoE server permit two clients with the same ip address
>Confidential:   no
>Severity:       serious
>Priority:       medium
>Responsible:    freebsd-bugs
>State:          closed
>Quarter:        
>Keywords:       
>Date-Required:  
>Class:          sw-bug
>Submitter-Id:   current-users
>Arrival-Date:   Mon Dec 05 16:10:02 GMT 2005
>Closed-Date:    Tue Dec 06 10:06:02 GMT 2005
>Last-Modified:  Tue Dec 06 10:06:02 GMT 2005
>Originator:     Frederico Boechat
>Release:        FreeBSD 6.0
>Organization:
>Environment:
FreeBSD kukimata.mar.com.br 6.0-STABLE FreeBSD 6.0-STABLE #0: Mon Dec  5 13:39:58 BRST 2005     root@kukimata.mar.com.br:/usr/obj/usr/src/sys/SMP  i386              
>Description:
We serve PPPoE connections to our wireless clients. The configuration files are the same of our FreeBSD 4.11 PPPoE server. But often we have two or more clients with different tunnels and the same ip address. The ip are dinamically distributed by PPPoE service. In the 4.11, I dont have this problem, the server reject the connection if the client gave the same ip address of other client.              
>How-To-Repeat:
set the same ip address in two different logins and then try to connect both...in 4.x series they cannot connect, but in the 5.x and 6.x series, they connect but none of them can ping to no one place.              
>Fix:
I dontknow how to fix this problem. I just know the 4.x series dont have this bug. Im not a good C programming...rs               
>Release-Note:
>Audit-Trail:
State-Changed-From-To: open->closed 
State-Changed-By: glebius 
State-Changed-When: Tue Dec 6 10:01:54 GMT 2005 
State-Changed-Why:  
Actually the PPP software or RADIUS should take care about colliding 
client IP addresses. Historically PPP software didn't do this relying 
on the fact that kernel will refuse such configuration. Meanwhile 
this configuration is valid and in some cases it is useful, and thus 
since FreeBSD 5.4-RELEASE kernel doesn't refuse same IP addresses 
on different interfaces. 

To assist software that relies on the old behavior a helper sysctl 
is available - net.inet.ip.same_prefix_carp_only. To get the old 
behavior you need to add the following line to your /etc/sysctl.conf: 

net.inet.ip.same_prefix_carp_only=1 

http://www.freebsd.org/cgi/query-pr.cgi?pr=89979 
>Unformatted:
