Hi everybody, Last week I posted a message concerning how to gain control on routing aliased IP with the goal to establish two gateways to the localnet. It became a problem 'two interfaces to same subnet'. Thanks to Martin for your hints: http://mailman.ds9a.nl/pipermail/lartc/2003q1/006930.html I've read the docs mentioned. The arp-flux problem should be solved by switching /proc/sys/net/ipv4/conf/(all,eth0,eth1)/arp_filter and ../rp_filter to 1. But there remained a problem. only one interface is ansering the arp requests, even for ip of the other interface. for more understanding this is my setup: hamburg:~# ip addr 1: lo: <LOOPBACK,UP> mtu 16436 qdisc noqueue link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00 inet 127.0.0.1/8 scope host lo 2: teql0: <NOARP> mtu 1500 qdisc noop qlen 100 link/void 3: dummy0: <BROADCAST,NOARP> mtu 1500 qdisc noop link/ether 00:00:00:00:00:00 brd ff:ff:ff:ff:ff:ff 4: bond0: <BROADCAST,MULTICAST,MASTER> mtu 1500 qdisc noop link/ether 00:00:00:00:00:00 brd ff:ff:ff:ff:ff:ff 5: eth0: <BROADCAST,MULTICAST,UP> mtu 1500 qdisc pfifo_fast qlen 100 link/ether 00:e0:7d:e2:9e:8d brd ff:ff:ff:ff:ff:ff inet 192.168.10.9/24 brd 192.168.10.255 scope global eth0 6: eth1: <BROADCAST,MULTICAST,UP> mtu 1500 qdisc pfifo_fast qlen 100 link/ether 00:e0:7d:e2:9e:8f brd ff:ff:ff:ff:ff:ff inet 192.168.10.8/24 brd 192.168.10.255 scope global eth1 7: eth2: <BROADCAST,MULTICAST,UP> mtu 1500 qdisc pfifo_fast qlen 100 link/ether 00:e0:7d:e2:9e:94 brd ff:ff:ff:ff:ff:ff inet 62.x.x.90/29 brd 62.x.x.95 scope global eth2 8: eth3: <BROADCAST,MULTICAST,UP> mtu 1500 qdisc pfifo_fast qlen 100 link/ether 00:e0:7d:e2:9e:96 brd ff:ff:ff:ff:ff:ff inet 62.x.x.90/29 brd 62.x.x.95 scope global eth3 9: eth4: <BROADCAST,MULTICAST,UP> mtu 1500 qdisc pfifo_fast qlen 100 link/ether 00:e0:7d:dc:95:2f brd ff:ff:ff:ff:ff:ff inet 192.168.11.8/24 brd 192.168.11.255 scope global eth4 hamburg:~# ip route 62.x.x.89 dev eth2 scope link 62.x.x.88/29 dev eth3 scope link 192.168.11.0/24 dev eth4 proto kernel scope link src 192.168.11.8 192.168.10.0/24 dev eth0 proto kernel scope link src 192.168.10.9 192.168.10.0/24 dev eth1 proto kernel scope link src 192.168.10.8 default via 62.x.x.89 dev eth0 from a host within the localnet an arping to both ips results in: moskau:~ # arping -c 3 192.168.10.9 ARPING 192.168.10.9 from 192.168.10.1 eth0 Unicast reply from 192.168.10.9 [00:E0:7D:E2:9E:8D] 0.665ms Unicast reply from 192.168.10.9 [00:E0:7D:E2:9E:8D] 0.619ms Unicast reply from 192.168.10.9 [00:E0:7D:E2:9E:8D] 0.619ms Sent 3 probes (1 broadcast(s)) Received 3 response(s) moskau:~ # arping -c 3 192.168.10.8 ARPING 192.168.10.8 from 192.168.10.1 eth0 Unicast reply from 192.168.10.8 [00:E0:7D:E2:9E:8D] 0.680ms Unicast reply from 192.168.10.8 [00:E0:7D:E2:9E:8D] 0.635ms Unicast reply from 192.168.10.8 [00:E0:7D:E2:9E:8D] 0.631ms Sent 3 probes (1 broadcast(s)) Received 3 response(s) so it seems for both arp-requests the interface eth0 on machine hamburg is responding. with the docs from julians site and others I think the arp response is based on the reverse routing path. both interfaces eth0 and eth1 set a path to the localnet 192.168.11.0/24. so eth0 responds for both ips becaue it's in the first place in the routing table. right? my next idea was to use julians 'ip arp' extension to iproute2, in order to gain control to the arp mechanism. I'm running a debian system with kernel 2.4.18 with lodable module support switched off and a minimal driver support, but all ipnetworking modules compiled in. I've downloaded ftp://ftp.inr.ac.ru/ip-routing/iproute2-2.4.7-now-ss020116-try.tar.gz http://www.linuxvirtualserver.org/~julian/iproute2-iparp-3.diff after unpacking the tar-ball and moving the directory iproute2 to iproute2-2.4.7-now-ss020116-try, I patched the source with hamburg:/usr/src# patch -p0 < iproute2-iparp-3.diff patching file iproute2-2.4.7-now-ss020116-try/ip/Makefile patching file iproute2-2.4.7-now-ss020116-try/ip/ip.c patching file iproute2-2.4.7-now-ss020116-try/ip/ip_common.h patching file iproute2-2.4.7-now-ss020116-try/ip/iparp.c patching file iproute2-2.4.7-now-ss020116-try/ip/ipmonitor.c (option -p1 didn't work, however) setting a link /usr/src/linux to my actual kernel source and running make in the iproute2 source directory ... somethings going terribly wrong. (...) gcc -D_GNU_SOURCE -O2 -Wstrict-prototypes -Wall -g -I../include-glibc -I/usr/include/db3 -include ../include-glibc/glibc-bugs.h -I/usr/src/linux/include -I../include -DRESOLVE_HOSTNAMES -c -o iproute.o iproute.c gcc -D_GNU_SOURCE -O2 -Wstrict-prototypes -Wall -g -I../include-glibc -I/usr/include/db3 -include ../include-glibc/glibc-bugs.h -I/usr/src/linux/include -I../include -DRESOLVE_HOSTNAMES -c -o iprule.o iprule.c gcc -D_GNU_SOURCE -O2 -Wstrict-prototypes -Wall -g -I../include-glibc -I/usr/include/db3 -include ../include-glibc/glibc-bugs.h -I/usr/src/linux/include -I../include -DRESOLVE_HOSTNAMES -c -o iparp.o iparp.c iparp.c:68: `ARPA_TABLE_INPUT' undeclared here (not in a function) iparp.c:68: initializer element is not constant iparp.c:68: (near initialization for `arp_tables[0].code') iparp.c:69: `ARPA_TABLE_OUTPUT' undeclared here (not in a function) iparp.c:69: initializer element is not constant iparp.c:69: (near initialization for `arp_tables[1].code') iparp.c:70: `ARPA_TABLE_FORWARD' undeclared here (not in a function) iparp.c:70: initializer element is not constant iparp.c:70: (near initialization for `arp_tables[2].code') iparp.c:113: `ARPA_TABLE_ALL' undeclared here (not in a function) iparp.c:113: initializer element is not constant iparp.c:113: (near initialization for `f.tb') iparp.c: In function `print_arprule': iparp.c:174: `RTM_NEWARPRULE' undeclared (first use in this function) iparp.c:174: (Each undeclared identifier is reported only once iparp.c:174: for each function it appears in.) iparp.c:174: `RTM_DELARPRULE' undeclared (first use in this function) iparp.c:180: dereferencing pointer to incomplete type iparp.c:184: dereferencing pointer to incomplete type iparp.c:187: dereferencing pointer to incomplete type (...) iparp.c:861: `ARPA_OIF' undeclared (first use in this function) iparp.c:879: `RTM_GETARPRULE' undeclared (first use in this function) make[1]: *** [iparp.o] Error 1 make[1]: Leaving directory `/usr/src/iproute2-2.4.7-now-ss020116-try/ip' make: *** [all] Error 2 can anybody tell me what's missing? ... and am I on the right way to solve my initial problem 'two interfaces on the same subnet?' thanks in advance, oli:-)
