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North American Network Operators Group Date Prev | Date Next | Date Index | Thread Index | Author Index | Historical Re: Router with 2 (or more) interfaces in same network
Leo Bicknell wrote: > > In a message written on Tue, Nov 11, 2003 at 08:35:34AM +0000, Sugar, Sylvia wrote: > > I am curious to know if its possible to have a router with its two interfaces, say configured as, > > 1.1.1.1/16 and 1.1.1.2/16. Theoretically, i see nothing which can stop a router from doing this. > > Cisco's don't let you do this. I have always considered that broken, > although I'm sure Cisco thinks it's a feature. Other routers (of > note FreeBSD boxes) do this just fine. Errr, no. FreeBSD won't let you do this. # ifconfig fxp0 inet 10.0.0.1 # ifconfig ep0 inet 10.0.0.2 ifconfig: ioctl (SIOCAIFADDR): File exists The error is a round-about way for the system to tell you, "hey, genius, I've already got a route for that network." 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, # ifconfig if0 inet 10.0.0.1 # ifconfig if0 alias 10.0.0.2 When they meant, # ifconfig if0 inet 10.0.0.1 # ifconfig if0 alias 10.0.0.2 netmask 0xffffffff But to reiterate the problem here, it's not really assigning addresses to interfaces, but trying to assign a route to the same network to different places. -- Crist J. Clark [email protected] Globalstar Communications (408) 933-4387
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