richard at syix.com
Fri Oct 1 16:58:50 PDT 2004
This is exactly what is happening.. I have found though that if I give
the interface two Ips with ifconfig and set the default route to our newest
router (Cisco 7204) somehow I am able to do what I am wanting. (I guess the
Cisco is lots smarter than our Tiara..) I am aware that having two numbered
networks on one physical lan is not good practice, but this is only a
temporary solution and VLANs are planned for the near future.. As for our
daemons, most are running promiscuous to any IP, but I am aware I will need
to "double check" the configs..
Thank you very much for your reply..
> -----Original Message-----
> From: Kevin Glick [mailto:keving at sbfnet.com]
> Sent: Friday, October 01, 2004 3:54 PM
> To: 'Richard Marriner'
> Cc: freebsd-questions at freebsd.org
> Subject: RE: Quickie... Hopefully!
> I've done the same thing a few times. To get the full
> description, check
> the ifconfig man page and look for "alias". There's two
> problems with doing
> this: first, BSD can't have two default routes. Windows
> allows you to set
> two default gateways, and it works because of the "Route
> Discovery" built
> into it (this is why a windows machine can use a gateway
> that's not on it's
> local subnet...but, that's another topic). Second, if you've
> got servers
> set to listen only on a specific IP (apache, etc) it still
> won't work, even
> with the alias.
> 220.127.116.11-18.104.22.168 -->from ISP #1 \
> /-> 22.214.171.124
> -->hub/switch -->
> FreeBSD fxp0
> 126.96.36.199-188.8.131.52 -->from ISP #2 /
> \-> 184.108.40.206
> In the crude diagram above, both ISPs feeds end up coming
> into a hub/switch
> that your BSD machine is plugged into. The normal ifconfig
> on the device is
> 220.127.116.11 netmask 255.255.255.0. You would then: "ifconfig
> fxp0 inet 18.104.22.168
> netmask 255.255.255.0 alias" the device. This will work, as
> long as routing
> is setup correctly. Any request for 22.214.171.124 from anywhere in
> the world
> would end up at the same machine/interface as a request for
> 126.96.36.199. The
> problem lies in getting data out with the aliased address.
> The default
> route on the machine would be 188.8.131.52 and all traffic goes
> there. If you
> have specific traffic that you want to go out with the
> 184.108.40.206 address,
> you'd have to add routes for each DESTINATION IP: "route add
> -net 220.127.116.11
> -netmask 255.255.255.0 18.104.22.168" and so on. BSD isn't smart
> enough to do
> source based routing. So the traffic will come into 22.214.171.124
> via ISP #2, but
> the replies/ACKs will go out via ISP #1. Any traffic
> generated from the
> machine, without a specified SOURCE IP will go out as
> 126.96.36.199, and get sent
> via the 188.8.131.52 gateway.
> The other problem with the diagram above is that you've got
> two subnets
> running on the same lan, which breaks most rules of
> networking. This can be
> remedied with a few vlans, but again, that's another topic.
> Hope this helps. I'm sure most of this info is correct, but
> I'm more than
> willing to have somebody set me straight.
> Kevin Glick
> ITS Manager
> keving at sbfnet.com
> Sterling Business Forms
> -----Original Message-----
> From: owner-freebsd-questions at freebsd.org
> [mailto:owner-freebsd-questions at freebsd.org] On Behalf Of
> Richard Marriner
> Sent: Friday, October 01, 2004 3:25 PM
> To: freebsd-questions at freebsd.org
> Subject: Quickie... Hopefully!
> Dear list,
> Just wondering if there is anyway (preferably simple.) to
> have two ip
> addresses on the same NIC that are different networks.
> A little background. We are in the process of changing ISPs,
> we now have
> two circuits going to two differnet ISPs. Because of this
> change we have to
> renumber our entire network. Being an ISP ourselves we have
> a handful of
> servers that run FreeBSD. While trying to get one of our
> test servers to
> talk to both networks from the internet we fail, I think
> because even though
> your request is on the new numbers FreeBSD still trys routing
> the response
> back through our old gateway. Another question, I know in
> Windows XP you
> can set two gateways, two ips, etc. Can you do this in FBSD?
> Our windows
> boxes are talking fine on both networks.
> Any help or suggestions appreciated...
> Richard Dean Marriner II
> SYIX.COM --=-- Network Administrator
> 530-755-1751x206 - richard at syix.com
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