Running dhclient on carp if

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Running dhclient on carp if

Jean-Christophe Sicard
Hi misc,

I'm trying to setup a pair of carp'ed firewalls on a cablemodem
connection with a single dhcp'ed IP.
The carp setup was a breeze on the internal interfaces where I have free
reing on IPs, but, not unexpectedly, the dhcp IP is proving a to be
challenge!
Searching around the archives, man pages and google turned up pretty
much only one other such attempt with no conclusiv solution...

My plan is/was to basically setup carp on my external interfaces with
carpdev, and then just run dhclient on the external carp interfaces on
both firewalls, which should give them the same IPs as they are
requesting for the same virtual MAC...

The issue as it is, is that I'm unable to properly run dhclient on the
carp interfaces, when they are in INIT state.  Eg:

carp1: flags=8802<BROADCAST,SIMPLEX,MULTICAST> mtu 1500
        carp: INIT carpdev xl1 vhid 2 advbase 1 advskew 128
        groups: carp egress
        inet 0.0.0.0 netmask 0x0
root@sentry2# dhclient carp1
DHCPREQUEST on carp1 to 255.255.255.255 port 67
send_packet: Network is unreachable
DHCPREQUEST on carp1 to 255.255.255.255 port 67
send_packet: Network is unreachable

If I give it a phony IP first (eg: ifconfig carp1 1.1.1.1 ), the carp
interface's state goes to master or backup (depending other carp peer)
and dhclient seems to find its way and is able to get an IP from the dhcp.
This workaround kinda works, but dhclient doesn't seem to be able to
renew properly and carp failover also seemed iffy (not fully tested at
this point).

So I guess my main question is, why can't dhclient get the carp ifs an
IP while they're in INIT state?

Secondary question would be, has anyone else tried / succeded in such a
setup?


TIA

JC

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Re: Running dhclient on carp if

Julian Smith
On Thu, 01 Dec 2005 00:23:27 -0500
Jean-Christophe Sicard <[hidden email]> wrote:

> Hi misc,
>
> I'm trying to setup a pair of carp'ed firewalls on a cablemodem
> connection with a single dhcp'ed IP.
> The carp setup was a breeze on the internal interfaces where I have free
> reing on IPs, but, not unexpectedly, the dhcp IP is proving a to be
> challenge!
> Searching around the archives, man pages and google turned up pretty
> much only one other such attempt with no conclusiv solution...
>
> My plan is/was to basically setup carp on my external interfaces with
> carpdev, and then just run dhclient on the external carp interfaces on
> both firewalls, which should give them the same IPs as they are
> requesting for the same virtual MAC...

Just in case anyone responds to this, could they reply to the list? I'd
like to know of a way to do this too.

- Julian

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