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Date: Mon, 11 May 1998 23:12:43 +0200 (CEST)
From: staffanu@nada.kth.se
Reply-To: staffanu@nada.kth.se
To: FreeBSD-gnats-submit@freebsd.org
Subject: Old IP address persistent after change
X-Send-Pr-Version: 3.2

>Number:         6595
>Category:       i386
>Synopsis:       Old IP address persistent after change
>Confidential:   no
>Severity:       non-critical
>Priority:       low
>Responsible:    freebsd-bugs
>State:          closed
>Quarter:        
>Keywords:       
>Date-Required:  
>Class:          sw-bug
>Submitter-Id:   current-users
>Arrival-Date:   Mon May 11 14:10:01 PDT 1998
>Closed-Date:    Sun Jun 02 04:36:32 PDT 2002
>Last-Modified:  Sun Jun 02 04:36:32 PDT 2002
>Originator:     Staffan Ulfberg
>Release:        FreeBSD 2.2.6-RELEASE i386
>Organization:
>Environment:
Tested on two installations of FreeBSD (2.2.6-RELEASE + unknown
version, probably 2.2.5 or 2.2.6).
>Description:
After the ip address of the computer is changed with ifconfig, the
source address of outgoing ip packets is set to the old ip address of
the machine.
>How-To-Repeat:
The following shows what happens when changing ip address from
62.20.128.20 to 62.20.128.21.  The test made is to ping the machine at
62.20.128.10.  

%%% tcpdump started %%%
chichi# tcpdump -n host 62.20.128.10
tcpdump: listening on zp0

%%% show ifconfig setup and ping other host %%%
chichi# ifconfig zp0
zp0: flags=1943<UP,BROADCAST,RUNNING,PROMISC,SIMPLEX,LINK0> mtu 1500
        inet 62.20.128.20 netmask 0xffffff80 broadcast 62.20.128.127
        ether 00:60:08:bb:d2:57 
chichi# ping 62.20.128.10
PING 62.20.128.10 (62.20.128.10): 56 data bytes
64 bytes from 62.20.128.10: icmp_seq=0 ttl=255 time=1.427 ms

%%% tcpdump output during ping %%%
21:50:55.556078 62.20.128.20 > 62.20.128.10: icmp: echo request
21:50:55.556504 62.20.128.10 > 62.20.128.20: icmp: echo reply

%%% reconfiguration of network interface %%%
chichi# ifconfig zp0 down
chichi# ifconfig zp0 inet 62.20.128.21 netmask 0xffffff80
chichi# ifconfig zp0
zp0: flags=1943<UP,BROADCAST,RUNNING,PROMISC,SIMPLEX,LINK0> mtu 1500
        inet 62.20.128.21 netmask 0xffffff80 broadcast 62.20.128.127
        ether 00:60:08:bb:d2:57 

%%% try to ping with new ip address %%%
chichi# ping 62.20.128.10
PING 62.20.128.10 (62.20.128.10): 56 data bytes
^C
--- 62.20.128.10 ping statistics ---
2 packets transmitted, 0 packets received, 100% packet loss

%%% tcpdump output during ping trial -- this is wrong! %%%
21:51:44.473753 62.20.128.20 > 62.20.128.10: icmp: echo request
21:51:44.474111 62.20.128.10 > 62.20.128.20: icmp: echo reply
21:51:45.480642 62.20.128.20 > 62.20.128.10: icmp: echo request
21:51:45.480990 62.20.128.10 > 62.20.128.20: icmp: echo reply

%%% delete route to remote host and try again %%%
chichi# route delete 62.20.128.10
delete host 62.20.128.10
chichi# ping 62.20.128.10
PING 62.20.128.10 (62.20.128.10): 56 data bytes
64 bytes from 62.20.128.10: icmp_seq=0 ttl=255 time=2.026 ms

%%% tcpdump output during ping %%%
21:52:16.564091 62.20.128.21 > 62.20.128.10: icmp: echo request
21:52:16.564454 62.20.128.10 > 62.20.128.21: icmp: echo reply
>Fix:
It seems that the old ip address is remembered on a per-route basis.
So, to complete the change of ip address, one can delete all routes
for the interface in question (of course a new default route has to be
added.)



>Release-Note:
>Audit-Trail:
Responsible-Changed-From-To: gnats-admin->freebsd-bugs@freebsd.org 
Responsible-Changed-By: phk 
Responsible-Changed-When: Wed May 13 00:30:15 PDT 1998 
Responsible-Changed-Why:  
misfiled 
Responsible-Changed-From-To: freebsd-bugs@freebsd.org->freebsd-bugs 
Responsible-Changed-By: steve 
Responsible-Changed-When: Sat May 23 20:40:58 PDT 1998 
Responsible-Changed-Why:  
'@freebsd-org' is not required. 
State-Changed-From-To: open->feedback 
State-Changed-By: iedowse 
State-Changed-When: Sat Jan 19 14:03:09 PST 2002 
State-Changed-Why:  

Does this problem still occur with more recent releases? 

http://www.FreeBSD.org/cgi/query-pr.cgi?pr=6595 
State-Changed-From-To: feedback->closed 
State-Changed-By: iedowse 
State-Changed-When: Sun Jun 2 04:36:04 PDT 2002 
State-Changed-Why:  

Feedback timeout. 

http://www.freebsd.org/cgi/query-pr.cgi?pr=6595 
>Unformatted:
