Date: 14 Aug 1995 10:55:11 +0800 From: peter@haywire.dialix.com (Peter Wemm) To: freebsd-current@freebsd.org Subject: Re: ioctl(SIOCAIFADDR): File exists Message-ID: <40mduf$fvb$1@haywire.DIALix.COM> References: <9508132011.AA10129@halloran-eldar.lcs.mit.edu>, <199508132043.WAA20874@uriah.heep.sax.de>
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j@uriah.heep.sax.de (J Wunsch) writes: >As Garrett Wollman wrote: >> >> > ioctl(SIOCAIFADDR): File exists >> >> 1) You have a bad combination of IP address and netmask, which overlaps >> something already configured in the system. Use the correct >> numbers. >193.175.26.94 --> 193.175.26.65 >netmask is 0xffffffe0, the primary ether interface is 193.175.26.33. There was a "feature" in 2.0.5 that meant that the local address of a point-to-point link could not be within the same network as any other interface, with the local subnet size being decided by the netmask of the remote network. ie: if you were on a C class, and had a ppp link to a class A network (ha! :-), you'd have to allocate another class-A network solely for each local address of each and every PPP/slip/ethernet link. The bug was that the netmask of the interface was incorrectly being applied to the local end of the interface, rather than the remote, or (better still) not applied at all. There is an undocumented option in the kernel, called something like P2P_LOCALADDR_SHARE, which works around the problem (with a slight bug) after I made a lot of noise about this "feature" before 2.0.5 was released. I'm happy to say that the fix has allowed us to quite happily use a stack of addresses sharing the same IP addresses.. :-) -Peter >-- >cheers, J"org >joerg_wunsch@uriah.heep.sax.de -- http://www.sax.de/~joerg/ >Never trust an operating system you don't have sources for. ;-)
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