Re: neighbor table overflow | |
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Marco C. Coelho wrote: > Looking into it further an ip route shows: > > 64.0.0.0/8 via 64.202.224.1 dev eth0 proto zebra metric 20 equalize This /8 doesn't affect the neighbor table. There must be a problem on the site that announce it > > So the 64.0.0.0 announce is coming into this box through OSPF (zebra) > > The 169.254.0.0/16 is being automajically added through the sysconfig > network scripts. I'm looking into why. > > In either case I still don't see why these entries would make the > neighbor table overflow. Could it have been the previous fix to the > hosts file? Well, when somebody try to make traffic with somebody from 169.254.0.0/16 throught you, your server will ask for arp on eth3, and most probably will record an <incomplete> entry in arp table. Virii and others can make this worse. Another quick fix is to drop arps from/to 169.254.0.0/16 with arptables. > > mc > > Alexandru Dragoi wrote: >> Marco C. Coelho wrote: >> >>> the ip route with a grep for link returns: >>> >>> snip** too long >>> 64.202.227.198 dev ppp436 proto kernel scope link src 10.20.1.1 >>> 64.202.227.196 dev ppp421 proto kernel scope link src 10.20.1.1 >>> 64.202.227.197 dev ppp211 proto kernel scope link src 10.20.0.1 >>> 64.202.227.194 dev ppp13 proto kernel scope link src 10.20.1.1 >>> 64.202.227.192 dev ppp404 proto kernel scope link src 10.20.1.1 >>> 64.202.227.254 dev ppp194 proto kernel scope link src 10.20.1.1 >>> 64.202.227.253 dev ppp130 proto kernel scope link src 10.20.1.1 >>> 64.202.227.252 dev ppp243 proto kernel scope link src 10.20.1.1 >>> 64.202.227.249 dev ppp195 proto kernel scope link src 10.20.1.1 >>> 64.202.227.248 dev ppp254 proto kernel scope link src 10.20.1.1 >>> 64.202.227.247 dev ppp235 proto kernel scope link src 10.20.1.1 >>> 64.202.227.242 dev ppp78 proto kernel scope link src 10.20.1.1 >>> 64.202.227.240 dev ppp328 proto kernel scope link src 10.20.1.1 >>> 64.202.227.237 dev ppp44 proto kernel scope link src 10.20.1.1 >>> 64.202.227.236 dev ppp122 proto kernel scope link src 10.20.1.1 >>> 64.202.227.234 dev ppp316 proto kernel scope link src 10.20.1.1 >>> 64.202.227.232 dev ppp132 proto kernel scope link src 10.20.1.1 >>> 64.202.227.231 dev ppp104 proto kernel scope link src 10.20.0.1 >>> 64.202.227.226 dev ppp179 proto kernel scope link src 10.20.0.1 >>> 64.202.224.0/24 dev eth0 proto kernel scope link src 64.202.224.8 >>> 192.168.1.0/24 dev eth3 proto kernel scope link src 192.168.1.8 >>> 169.254.0.0/16 dev eth3 scope link >>> >> >> The one above must be deleted, many redhat-like distros attach >> 169.254.0.0/16. >> >>> All the pppoe terminations (pppd) are shown, as well as the last three >>> subnets. I'll have to see where the 169.254.0.0/16 is coming from? >>> >>> mc >>> >>> >>> >>> >>> Alexandru Dragoi wrote: >>> >>>> Marco C. Coelho wrote: >>>> >>>> >>>>> This box is doing a lot. It terminates 1000 PPPoE connections, >>>>> provides traffic shaping using TC/HTB, authenticates all users via >>>>> Radius. It also runs OSPF routing for the internal network. Looking >>>>> at a simple route output I see all the PPP connections coming through >>>>> the box, and due to the OSPF I also see the rest of my network >>>>> announcements. The only strange things are: >>>>> >>>>> 1. The last man working on this box had mistakenly edited the hosts >>>>> file and added the machine name and complete domain name to the local >>>>> host 127.0.0.1 name. It should only be pointed to the eth0 >>>>> interface. I have changed this. >>>>> >>>>> 2. The route output is making an announcement >>>>> >>>>> 64.0.0.0 argontech.net 255.0.0.0 UG 20 >>>>> 0 0 eth0 >>>>> >>>>> >>>> This doesn't look dangerous for your problem, I was only talking about >>>> directly connected networks: >>>> >>>> # ip route |grep link >>>> >>>> >>>> >>>>> My public IP space is a /20 within that space, not the whole Class A. >>>>> I have not found which box is announcing this within my network yet. >>>>> >>>>> >>>>> >>>>> >>>>> >>>>> Jeff Welling wrote: >>>>> >>>>> >>>>>>> On 10/23/07 06:56, Alexandru Dragoi wrote: >>>>>>> >>>>>>> >>>>>>>> What about checking your routing table? you may have link routes >>>>>>>> for massive subnets (like 85.0.0.0/8 or 140.20.0.0/16). Some >>>>>>>> programs prefer to use "standard" netmask of classes A and B. >>>>>>>> >>>>>>>> >>>>>>> I'm betting that the OP has other things going on seeing has how >>>>>>> s/he mentioned PPPoE, which to my knowledge is a layer 2 protocol, >>>>>>> and thus not subject to typical routing scenarios. In essence the >>>>>>> OP could have thousands of PPPoE connections terminating on one >>>>>>> system with the ARP cache having to deal with where to send traffic >>>>>>> to which MAC address. There is not a lot of room for routing in such >>>>>>> a scenario. >>>>>>> >>>>>>> >>>>>>> >>>>>> I agree with Peter's suggestion, arpd. I ran into the neighbor table >>>>>> overflow problem recently, at the hands of our ISP. I was in the >>>>>> process of recompiling the kernel and mucking with arpd (I couldn't >>>>>> get it to run/start properly) when the problem disappeared as quickly >>>>>> as it showed up. Lucky for me, this was some kind of ISP problem, I >>>>>> was able to determine that much through `tcpdump -i X -n arpd`. >>>>>> >>>>>> My 'two cents' is that you try arpd, I did a bit of looking when I >>>>>> came across that problem and it seemed to be the last ditch effort >>>>>> when changing the gc threshold had no effect. Wasn't able to confirm >>>>>> that it worked for sure though. >>>>>> >>>>>> Cheers. >>>>>> _______________________________________________ >>>>>> LARTC mailing list >>>>>> LARTC@xxxxxxxxxxxxxxx >>>>>> http://mailman.ds9a.nl/cgi-bin/mailman/listinfo/lartc >>>>>> >>>>>> >>>>>> >>>>> _______________________________________________ >>>>> LARTC mailing list >>>>> LARTC@xxxxxxxxxxxxxxx >>>>> http://mailman.ds9a.nl/cgi-bin/mailman/listinfo/lartc >>>>> >>>>> >>>> >>>> >>> ------------------------------------------------------------------------ >>> >>> _______________________________________________ >>> LARTC mailing list >>> LARTC@xxxxxxxxxxxxxxx >>> http://mailman.ds9a.nl/cgi-bin/mailman/listinfo/lartc >>> >>> >> >> >> _______________________________________________ LARTC mailing list LARTC@xxxxxxxxxxxxxxx http://mailman.ds9a.nl/cgi-bin/mailman/listinfo/lartc