On Fri, Jan 22, 2010 at 11:09:02AM +0100, Fredrik Ax wrote: > Hi guys, > > I'm a pretty experienced Linux / network developer and administrator, > but I can't get my head around this one. > > The long story is that I have a box used as router/fw/proxy running > Debian Squeeze with a customized 2.6.32 x86_64 kernel having three > interfaces (eth2,eth3,eth4) on the same external subnet. One of the > interfaces is used for doing masquerading of other > subnets. Masquerading (not snat) is chosen because the interfaces are > on dhcp, and I don't want to have to rewrite the fw rules each time I > get a new addr ... already have enough with dhclient-hooks for fixing > the routing tables dns-updates, etc ;-) What I basically want to do is > make the proxy's request to go out the same ifc as the masqueraded > packets getting a src addr of s41.s42.s43.s44. Other locally generated > packets should get a src addr s21.s22.s23.s24. > > To accomplish this I'm using iptables to mark all, to port 80, locally > generated tcp packets: > > % iptables -t mangle -vnL OUTPUT > Chain OUTPUT (policy ACCEPT 3234 packets, 2254K bytes) > pkts bytes target prot opt in out source destination > 1114 181K MARK tcp -- * * 0.0.0.0/0 0.0.0.0/0 tcp dpt:80 MARK set 0x4 > > I have verified that the iptables rule marks them fine enough. > > Then the ip rule with prio 99 below should then catch them and route > according to table eth4 below. That rule however does, for some reason > not match those packets, instead they are routed according to table > eth2 below (prio 200 rule), getting src addr s21.s22.s23.s24. If I > disable that rule they are routed according the the prio 300 rule > (getting src addr s31.s32.s33.s34). > > prompt% ip rule > 0: from all lookup local > 1: from all lookup main > 99: from all fwmark 0x4 lookup eth4 > 100: from 10.116.254.0/26 lookup eth4 > 100: from 10.116.255.34 lookup eth3 > 100: from 10.116.255.64/26 lookup eth4 > 200: from all lookup eth2 > 300: from all lookup eth3 > 400: from all lookup eth4 > 32767: from all lookup default > > prompt% ip route show table eth2 > broadcast b1.b2.b3.b4 dev eth2 scope link src s21.s22.s23.s24 > broadcast n1.n2.n3.n4 dev eth2 scope link src s21.s22.s23.s24 > n1.n2.n3.n4/m dev eth2 scope link src s21.s22.s23.s24 > default via g1.g2.g3.g4 dev eth2 src s21.s22.s23.s24 > > prompt% ip route show table eth3 > broadcast b1.b2.b3.b4 dev eth3 scope link src s31.s32.s33.s34 > broadcast n1.n2.n3.n4 dev eth3 scope link src s31.s32.s33.s34 > n1.n2.n3.n4/m dev eth3 scope link src s31.s32.s33.s34 > default via g1.g2.g3.g4 dev eth3 src s31.s32.s33.s34 > > prompt% ip route show table eth4 > broadcast b1.b2.b3.b4 dev eth4 scope link src s41.s42.s43.s44 > broadcast n1.n2.n3.n4 dev eth4 scope link src s41.s42.s43.s44 > n1.n2.n3.n4/m dev eth4 scope link src s41.s42.s43.s44 > default via g1.g2.g3.g4 dev eth4 src s41.s42.s43.s44 You might also want to know that the local routes for eth2-4 are removed in the local table, and that the main table holds no default routes. > > What am I doing wrong here? > > TIA > /frax ______________________________________________________________________ This email has been scanned by the MessageLabs Email Security System. For more information please visit http://www.messagelabs.com/email ______________________________________________________________________ -- To unsubscribe from this list: send the line "unsubscribe linux-net" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
