Date: Mon, 14 Dec 1998 21:54:52 -0500 From: Graeme Tait <graeme@echidna.com> To: Dan Busarow <dan@dpcsys.com> Cc: Lew Payne <lewiz@netcom.com>, freebsd-questions@FreeBSD.ORG Subject: Re: Strange Network Problem Message-ID: <3675CF7C.671A@echidna.com> References: <Pine.BSF.3.96.981214162705.24918A-100000@java.dpcsys.com>
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I found the following (evidently written some time ago) which confirms what Dan Busarow wrote, and expands on it: http://www.cypher.net/~black/ipalias.html Quoting from the above: "First, there is a bug in all distributions of bind (the named DNS server is part of BIND) that prevents named from starting properly when there are more than 64 aliases on an interface." Is this still true? Dan Busarow wrote: <snip> > Stuff below assumes 0xffffff00 is the correct netmask for the network. > s/0xffffff00/your_netmask/g if this is not the case. > > When you ifconfig the "real" IP address, eg > > ifconfig ed1 192.168.1.1 netmask 0xffffff00 > > you also setup a static route and create an arp entry. When you > add the aliased IPs all you need to add are a host route to the new > IP (netmask 0xffffffff) and an arp entry. An ifconfig like > > ifconfig ed1 192.168.1.2 netmask 0xffffffff alias > > does that. > > If you use a netmask of 0xffffff00 for the alias you get an error > when adding the static route, because it already exists. Since the > route addition failed the arp entry doesn't get made (I'm guessing here, > I haven't actually confirmed that this is why the arp isn't added. > but I do know that it does not get added). > > A netmask of 0xffffff00 "works" for aliases (assuming that's the correct > netmask) but it causes an error message and you can't ping the alias > or telnet to the alias from the host machine unless you manually add > an arp entry. You also can't "ifconfig ed1 192.168.1.2 delete" the > alias if it was created with a netmask 0xffffff00 so if you make a > mistake you're stuck with it. > > A netmask of 0xffffffff just plain works (as long as the aliased IP falls > within the subnet defined by the netmask on the primary IP). > > Use whichever method you prefer. I prefer the one that has one less step > and doesn't generate an error message :) -- Graeme Tait - Echidna To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-questions" in the body of the message
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