Re: multiple interfaces on same subnet?
On 7/31/06, Joseph Gleason [EMAIL PROTECTED] wrote: Is it possible to reach two hosts via two interfaces that are both on the same subnet? ... My objective is to have a FreeBSD box balance outbound traffic between two NICs, while being able to select from among many routers that could be the default gateway and having the two NICs connect to different switches for fault tolerance. (I would do the fault tolerance via a watchdog script of some sort) Take a look at pf. pf has some very powerful nat rules that should be able to do what you want. Use a table to specify the next-hop and use a pfctl script for your watchdog. -- -- Perfection is just a word I use occasionally with mustard. --Atom Powers-- ___ freebsd-questions@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-questions To unsubscribe, send any mail to [EMAIL PROTECTED]
Re: multiple interfaces on same subnet?
On Tue, 1 Aug 2006 05:10 am, Joseph Gleason wrote: Is it possible to reach two hosts via two interfaces that are both on the same subnet? Example: em0: 172.20.0.1/16 em1: 172.20.0.2/16 And I want to reach 172.20.0.3 via em0 and 172.20.0.4 via em1. From 'netstat -nr' I see a line like this: 172.20/14 link#1 UC 00 em0 This seems to say that anything on 172.20/14 should be reached on em0. Is it possible to add a rule that says that 172.20.0.4 should be reachable on em1? I have no personal experience of doing this, but it seems to me you should be able to achieve your objective by using a specific netmask with ifconfig rather than the CIDR / notation: 172.20.0.1/16 - 172.20.0.1 netmask 255.255.0.1 172.20.0.2/16 - 172.20.0.1 netmask 255.255.0.1 Then as I understand it odd numbered addresses should be reached via 172.20.0.1 and even numbered addresses via 172.20.0.2 I only care about the path of outbound packets. I don't care which interface inbound traffic comes on. I am well aware that this is a fairly strange thing to do. My objective is to have a FreeBSD box balance outbound traffic between two NICs, while being able to select from among many routers that could be the default gateway and having the two NICs connect to different switches for fault tolerance. (I would do the fault tolerance via a watchdog script of some sort) If it weren't for the many routers aspect, it would be reasonable to create separate subnets. I need to be able to select from a group of around 10 possible default gateways and some of those routers I do not control so adding a subnet would be trouble. I would expect that subnets in the routers would not be an issue so long as they encompass those set in ifconfig. Malcolm ___ freebsd-questions@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-questions To unsubscribe, send any mail to [EMAIL PROTECTED]
Re: multiple interfaces on same subnet?
On 8/1/06, Malcolm Kay [EMAIL PROTECTED] wrote: I have no personal experience of doing this, but it seems to me you should be able to achieve your objective by using a specific netmask with ifconfig rather than the CIDR / notation: 172.20.0.1/16 - 172.20.0.1 netmask 255.255.0.1 172.20.0.2/16 - 172.20.0.1 netmask 255.255.0.1 Creative idea ... even if it's breaking the rules ( so don't do it ). Even if FreeBSD honors these subnets there is no guarantee that any other hosts on the network will. Many systems will refuse to even configure this kind of invalid subnet. Plus, you can't easily scale this to the 10 networks the original poster mentioned and it would be a nightmare to try and figure out how to re-route traffic if one of the next-hop hosts died. (Which was also a goal mentioned in the original post.) Although I've head that IPFW can handle multiple dynamic redirects ( I forswore all other firewalls as soon as I found pf ) you can do it very simply with pf. -- -- Perfection is just a word I use occasionally with mustard. --Atom Powers-- ___ freebsd-questions@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-questions To unsubscribe, send any mail to [EMAIL PROTECTED]
