Date: Sat, 9 Aug 2008 08:37:22 -1000 From: Clifton Royston <cliftonr@lava.net> To: KES <kes-kes@yandex.ru> Cc: freebsd-stable@freebsd.org Subject: Re: Fwd: IMPORTANT! Network is unreachable Message-ID: <20080809183721.GA9982@lava.net> In-Reply-To: <358831218288212@webmail24.yandex.ru> References: <358831218288212@webmail24.yandex.ru>
next in thread | previous in thread | raw e-mail | index | archive | help
On Sat, Aug 09, 2008 at 05:23:32PM +0400, KES wrote: > 09.08.08, 16:22, "Matthew Seaman" <m.seaman@infracaninophile.co.uk>: > > Andrew Snow wrote: > > > Usually if there is more than IP in a given subnet on an interface, you > > > give it a /32 netmask. Only the first IP in a subnet should have the > > > full netmask. > > > > > > So your example should look like this: > > > > > > inet 10.11.16.14 netmask 0xffffff00 broadcast 10.11.16.255 > > > inet 10.11.16.9 netmask 0xffffffff broadcast 10.11.16.9 > > /32 netmasks for 2nd and subsequent IP alias addresses used to be > > mandatory and are arguably more correct, but nowadays you can use > > the actual netmask for the network instead. Was fixed a year or > > two ago. It's a wetware compatibility thing -- other unixoid OSes > > never had the /32 netmask requirement, and it kept tripping people up > > when swapping between OSes. > > Unfortunately I can't say exactly what the problem the OP is experiencing > > is due to, but the way routes are appearing and disappearing on a 5 > > minute timescale does suggest dynamic routing problems to me. As a > > work-around, if the OP wanted to override the information routed gets > > from the network, then he could use /etc/gateways to have the local > > routed append some static routes to the routing table -- see routed(8) > > for the gory details. Losing a route for a directly attached network > > looks like a bug to me though. ... > > > > inet 10.11.16.14 netmask 0xffffff00 broadcast 10.11.16.255 > > > inet 10.11.16.9 netmask 0xffffffff broadcast 10.11.16.9 > /24 mask on each IPs on same interfaces is working fine on FreeBSD 6.3 > So I do not think that problem is with the network mask. Because of even ping 10.11.16.14 > returns network is unreachable! > Now when I upgraded to v7 I see trouble described earlier. > So this is must be counted as BUG of v7 I happened to see recently a report of a similar problem with 7.0 on a private mailing list. Again, there were multiple IP addresses configured within the main subnet of the interface (this time configured as /32s on other physical interfaces) and again, after a while the system lost connectivity to its main subnet and "forgot" how to ARP for addresses on the interface. An important similarity - the routing info like yours showed the attached network with the G flag, as being reachable via the gateway address within the same subnet. I can't troubleshoot this, no access to the system in question, but I thought it might help to know that others have run into the same problem. > The thing which is very interesting is: > Why period is 5 min? Might be something to do with ARP? Not sure. -- Clifton -- Clifton Royston -- cliftonr@iandicomputing.com / cliftonr@lava.net President - I and I Computing * http://www.iandicomputing.com/ Custom programming, network design, systems and network consulting services
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?20080809183721.GA9982>