From: CCIE KH49279 (ccie_lab@inetiq.com)
Date: Wed Apr 26 2006 - 00:55:26 GMT-3
Ultimately this is what I have gathered from the responses.
Using multiple default-router addresses in the DHCP configuration will yield
a less than desirable gateway redundancy based upon host parameters (i.e.
ARP timeouts, number of default-router addresses a host will accept), and
the only network controlled piece is really the assignment of the
default-router addresses.
In a scenario where HSRP is not allowed, using VRRP would be the most
appropriate, and it looks as if IRDP would be a better solution than using
default-router (i.e. host selection of gateways) assuming the host were
capable of IRDP.
Thoughts or comments, otherwise I think I have it and will let it rest.
Thanks for those who responded both publicly and privately.
Regards,
Wayne
-----Original Message-----
From: nobody@groupstudy.com [mailto:nobody@groupstudy.com] On Behalf Of
Aaron Pilcher
Sent: Tuesday, April 25, 2006 9:20 PM
To: 'Jung-I Lin'; 'CCIE KH49279'
Cc: 'Cisco certification'
Subject: RE: DHCP default-router
One of the problems, with clients handling first hop redundancy, is that
they will only stop sending traffic to the primary default GW when their ARP
entry for it ages out. I think the arp time out is 2 min by default,
therefore from the moment the "primary" router goes down there will be a 2
min gap for off local network communications.
'just cause you can do something...doesn't necessarily mean you should
-----Original Message-----
From: nobody@groupstudy.com [mailto:nobody@groupstudy.com] On Behalf Of
Jung-I Lin
Sent: Tuesday, April 25, 2006 8:59 PM
To: CCIE KH49279
Cc: Cisco certification
Subject: Re: DHCP default-router
Hi, Wayne
You can have certain level of redundancy by configuring multiple
default-gateway on WinXP or Win2k3.
See the url
http://www.microsoft.com/technet/community/columns/cableguy/cg0903.mspx#EPH
HTH.
On 4/26/06, CCIE KH49279 <ccie_lab@inetiq.com> wrote:
> Group,
>
> I am a bit confused about the use of the default-router command in DHCP.
>
> I understand the function of the command and the information it will cause
> the dhcp server to provide to the host.
>
> However, the documentation mentions that up to 8 default-routers can be
> assigned under this command. To me this suggest that you can provide some
> level (albeit not very flexible) of gateway redundancy. I unfortunately
have
> no facility to test this critter so I am posting to the group for your
> assistance and knowledge.
>
> What happens if I use this as part of my configuration:
>
> Default-router 192.168.10.1 192.168.10.2 192.168.10.3
>
> If for instance the host initially gets 10.1 assigned as the
> default-gateway, and then during the lease period 10.1 becomes
unreachable,
> will the host automatically switch to the 10.2 gateway, or will the host
> query the dhcp server again and then be assigned the 10.2 address, or ???
>
>
> Thanks in Advance,
>
> Wayne
>
> _______________________________________________________________________
> Subscription information may be found at:
> http://www.groupstudy.com/list/CCIELab.html
>
-- Thanks Best Regards,Jung-I Lin
This archive was generated by hypermail 2.1.4 : Mon May 01 2006 - 11:41:59 GMT-3