In a message written on Tue, Nov 11, 2003 at 09:38:23AM -0800, Crist Clark wrote:
You _used_ to be able to do this (oh, over two years ago?). The address was assigned to the interface, and the error from trying to add a duplicate route was simply ignored, no route got added anywhere. You can figure out when the change was made by examining the code or by seeing when the maillists started to get flooded by people who could no longer do,
When the code changed to support multiple IP's on a single interface it changed the way you configure this in FreeBSD land: testbox# ifconfig fxp1 fxp1: flags=8802<BROADCAST,SIMPLEX,MULTICAST> mtu 1500 ether 00:02:b3:3e:a7:e6 media: Ethernet autoselect (none) status: no carrier testbox# ifconfig fxp2 fxp2: flags=8802<BROADCAST,SIMPLEX,MULTICAST> mtu 1500 ether 00:02:b3:3e:a5:f1 media: Ethernet autoselect (none) status: no carrier testbox# ifconfig fxp1 inet 10.10.10.1 netmask 255.255.255.0 testbox# ifconfig fxp2 inet 10.10.10.2 netmask 255.255.255.255 testbox# ifconfig fxp1 fxp1: flags=8843<UP,BROADCAST,RUNNING,SIMPLEX,MULTICAST> mtu 1500 inet 10.10.10.1 netmask 0xffffff00 broadcast 10.10.10.255 inet6 fe80::202:b3ff:fe3e:a7e6%fxp1 prefixlen 64 scopeid 0x2 ether 00:02:b3:3e:a7:e6 media: Ethernet autoselect (none) status: no carrier testbox# ifconfig fxp2 fxp2: flags=8843<UP,BROADCAST,RUNNING,SIMPLEX,MULTICAST> mtu 1500 inet6 fe80::202:b3ff:fe3e:a5f1%fxp2 prefixlen 64 scopeid 0x4 inet 10.10.10.2 netmask 0xffffffff broadcast 10.10.10.2 ether 00:02:b3:3e:a5:f1 media: Ethernet autoselect (none) status: no carrier Just like an alias, the second (to nth) IP on a lan must have a host netmask due to the way the routing code works. If you plug both of these into a switch and put a host on the other end, traffic to .1 will go to fxp1, traffic to .2 will go to fxp2. Traffic leaving the box will use fxp1 only. At least, it worked this way the last I tested with 4.8, I haven't tried with the 5.x tree, but the box I did the test above on was a -current box. I shouldn't have opened my mouth. When you admit to knowing how to make a gross hack work it seems everyone wants to e-mail you about how it is a gross hack, or about all the picky details of how it works. :) -- Leo Bicknell - bicknell@ufp.org - CCIE 3440 PGP keys at http://www.ufp.org/~bicknell/ Read TMBG List - tmbg-list-request@tmbg.org, www.tmbg.org