NetBSD Problem Report #11102

Received: (qmail 9185 invoked from network); 30 Sep 2000 00:21:51 -0000
Message-Id: <200009300021.e8U0Lpj15266@fartmangler.redback.com>
Date: Fri, 29 Sep 2000 17:21:51 -0700 (PDT)
From: dogcow@redback.com
Reply-To: dogcow@netbsd.org
To: gnats-bugs@gnats.netbsd.org
Subject: <synopsis of the problem (one line>netbooted dhclient causes hang when moved to other subnet
X-Send-Pr-Version: 3.95

>Number:         11102
>Category:       bin
>Synopsis:       netbooted dhclient causes hang when moved to other subnet
>Confidential:   no
>Severity:       serious
>Priority:       high
>Responsible:    mellon
>State:          closed
>Class:          sw-bug
>Submitter-Id:   net
>Arrival-Date:   Sat Sep 30 00:22:00 +0000 2000
>Closed-Date:    Thu Jan 15 23:07:58 +0000 2015
>Last-Modified:  Thu Jan 15 23:07:58 +0000 2015
>Originator:     Tom Spindler
>Release:        20000913
>Organization:
Redback Networks

>Environment:

System: NetBSD fartmangler.redback.com 1.5_ALPHA2 NetBSD 1.5_ALPHA2 (NETZUUL) #10: Fri Sep 15 15:34:13 PDT 2000 notroot@zuul.redback.com:/amd/netapp6/netbsd15/nbsrc/sys/arch/i386/compile/NETZUUL i386


>Description:
If you netboot a netbsd machine with root nfs mounted and use
dhclient to assign the address, dhclient will config your ether
iface address to be that it finds in /var/db/dhcpd.leases - before
it gets an ACK that it's the correct address to use. If you've
previously booted the machine on a different dhcp'ed subnet, the
lease will contain an address such that the default gateway becomes
unreachable - and your nfs mount of / will go away and cause the
boot to hang.

>How-To-Repeat:
Netboot netbsd machine with / on NFS on one subnet.
Reassign machine and address to different subnet. 
Boot hangs in dhclient because iface is mis-set and root goes away.

>Fix:

Fix: Don't change the enet iface's address until a succesful ACK from the DHCP
server.

Workaround: always delete /var/db/dhcpd.leases on reboot.
>Release-Note:
>Audit-Trail:

From: Manuel Bouyer <bouyer@antioche.lip6.fr>
To: dogcow@redback.com
Cc: gnats-bugs@gnats.netbsd.org, netbsd-bugs@netbsd.org
Subject: Re: bin/11102: <synopsis of the problem (one line>netbooted dhclient causes hang when moved to other subnet
Date: Sat, 30 Sep 2000 14:24:44 +0200

 On Fri, Sep 29, 2000 at 05:21:51PM -0700, dogcow@redback.com wrote:
 > 
 > >Number:         11102
 > >Category:       bin
 > >Synopsis:       <synopsis of the problem (one line>netbooted dhclient causes hang when moved to other subnet
 > >Confidential:   no
 > >Severity:       serious
 > >Priority:       high
 > >Responsible:    bin-bug-people
 > >State:          open
 > >Class:          sw-bug
 > >Submitter-Id:   net
 > >Arrival-Date:   Fri Sep 29 17:22:00 PDT 2000
 > >Closed-Date:
 > >Last-Modified:
 > >Originator:     Tom Spindler
 > >Release:        <NetBSD-current source date> 13 Sep 2000
 > >Organization:
 > Redback Networks
 > 	
 > >Environment:
 > 	
 > System: NetBSD fartmangler.redback.com 1.5_ALPHA2 NetBSD 1.5_ALPHA2 (NETZUUL) #10: Fri Sep 15 15:34:13 PDT 2000 notroot@zuul.redback.com:/amd/netapp6/netbsd15/nbsrc/sys/arch/i386/compile/NETZUUL i386
 > 
 > 
 > >Description:
 > If you netboot a netbsd machine with root nfs mounted and use
 > dhclient to assign the address, dhclient will config your ether
 > iface address to be that it finds in /var/db/dhcpd.leases - before
 > it gets an ACK that it's the correct address to use. If you've
 > previously booted the machine on a different dhcp'ed subnet, the
 > lease will contain an address such that the default gateway becomes
 > unreachable - and your nfs mount of / will go away and cause the
 > boot to hang.
 > 	
 > >How-To-Repeat:
 > Netboot netbsd machine with / on NFS on one subnet.
 > Reassign machine and address to different subnet. 
 > Boot hangs in dhclient because iface is mis-set and root goes away.
 > 	
 > >Fix:
 > 	
 > Fix: Don't change the enet iface's address until a succesful ACK from the DHCP
 > server.

 Hum, I think this should be made optional. If I understood it properly, this
 behavior is intentional, to get a working machine even if the DHCP server
 is down. WinNT behaves the same way.
 DHCP is also used for desktops, as a way to centralise network configs.

 --
 Manuel Bouyer <bouyer@antioche.eu.org>
 --

From: David Brownlee <abs@netbsd.org>
To: Manuel Bouyer <bouyer@antioche.lip6.fr>
Cc: dogcow@redback.com, gnats-bugs@gnats.netbsd.org, netbsd-bugs@netbsd.org
Subject: Re: bin/11102: <synopsis of the problem (one line>netbooted dhclient
 causes hang when moved to other subnet
Date: Mon, 2 Oct 2000 08:01:40 +0100 (BST)

 On Sat, 30 Sep 2000, Manuel Bouyer wrote:

 > On Fri, Sep 29, 2000 at 05:21:51PM -0700, dogcow@redback.com wrote:
 > > Fix: Don't change the enet iface's address until a succesful ACK from the DHCP
 > > server.
 > 
 > Hum, I think this should be made optional. If I understood it properly, this
 > behavior is intentional, to get a working machine even if the DHCP server
 > is down. WinNT behaves the same way.
 > DHCP is also used for desktops, as a way to centralise network configs.

 	True, but deferring making any changes to the interface until either
 	an ACK or timeout has occured would not affect the normal case.
 	Alternatively, defer the changaes iff the interface already has an
 	address.

                 David/absolute
 			       -- www.netbsd.org: A pmap for every occasion --



From: Manuel Bouyer <bouyer@antioche.lip6.fr>
To: David Brownlee <abs@netbsd.org>
Cc: dogcow@redback.com, gnats-bugs@gnats.netbsd.org, netbsd-bugs@netbsd.org
Subject: Re: bin/11102: <synopsis of the problem (one line>netbooted dhclient causes hang when moved to other subnet
Date: Mon, 2 Oct 2000 11:23:11 +0200

 On Mon, Oct 02, 2000 at 08:01:40AM +0100, David Brownlee wrote:
 > 	True, but deferring making any changes to the interface until either
 > 	an ACK or timeout has occured would not affect the normal case.
 > 	Alternatively, defer the changaes iff the interface already has an
 > 	address.

 Ok, this looks like a better behavior.

 --
 Manuel Bouyer, LIP6, Universite Paris VI.           Manuel.Bouyer@lip6.fr
 --
Responsible-Changed-From-To: bin-bug-people->mellon 
Responsible-Changed-By: fair 
Responsible-Changed-When: Wed Mar 21 20:22:07 PST 2001 
Responsible-Changed-Why:  
Ted Lemon is our DHCP expert. 
State-Changed-From-To: open->feedback
State-Changed-By: dholland@NetBSD.org
State-Changed-When: Wed, 14 Jan 2015 03:59:05 +0000
State-Changed-Why:
Is this issue still current? (it is nearly fifteen years since it was last
touched...)


State-Changed-From-To: feedback->closed
State-Changed-By: dholland@NetBSD.org
State-Changed-When: Thu, 15 Jan 2015 23:07:58 +0000
State-Changed-Why:
Submitter says to close it.


>Unformatted:

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