I'm still stuck on this one and could really use some help. I just finished trying it on an FC3 box too to make sure it wasn't CentOS specific issue but there's still no output from tcpdump. I also spent some time looking over Cisco examples to make sure I wasn't misremembering the concepts. No surprises there. Does anyone have any ideas or can someone suggest a more appropriate forum for the question? Thanks!! On 6/21/07 11:52 AM, "Greg Hartung" <ghartung@xxxxxxxxxxxxxxx> wrote: > > I am trying to setup GRE between two CentOS 4.5 boxes. I have tried > several variations of what's listed below, but none of them work. > > box1: > modprobe ip_gre > ip link set gre0 up > ip tunnel add gretun mode gre local 66.1.1.161 remote 66.1.2.161 ttl 20 dev > eth0 > ip addr add dev gretun 10.253.253.1 peer 10.253.253.2/24 > ip link set dev gretun up > ip route add 10.2.0.0/16 via 10.253.253.2 > > box2: > modprobe ip_gre > ip link set gre0 up > ip tunnel add gretun mode gre local 66.1.2.161 remote 66.1.1.161 ttl 20 dev > eth0 > ip addr add dev gretun 10.253.253.2 peer 10.253.253.1/24 > ip link set dev gretun up > ip route add 10.1.0.0/16 via 10.253.253.1 > > tcpdump shows NO rx or tx traffic from either box that isn't ARP or SSH. > > It's as if it's not even trying to bring the tunnel up. I'm a Cisco guy, > so I'm lost with my show commands. > > The other variations I've tried consist mostly of trying different > combinations of on-net (in the same subnet as eth0 and even the same address > as eth0) and off-net (various combinations of loopback /24 and /32 addresses > in separate 10 space) on the 'ip addr add dev gretun' statements. But the > above example is what *should* work on a Cisco, I think. It's been a > while. > > How do I troubleshoot this? This is all I've got so far: > > root@den1tun01:/home/root $ ip link > 1: lo: <LOOPBACK,UP> mtu 16436 qdisc noqueue > link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00 > 2: eth0: <BROADCAST,MULTICAST,UP> mtu 8800 qdisc pfifo_fast qlen 1000 > link/ether 00:19:b9:dd:ff:d9 brd ff:ff:ff:ff:ff:ff > 3: eth0.2: <BROADCAST,MULTICAST,UP> mtu 8800 qdisc noqueue > link/ether 00:19:b9:dd:ff:d9 brd ff:ff:ff:ff:ff:ff > 4: gre0: <NOARP,UP> mtu 1476 qdisc noqueue > link/gre 0.0.0.0 brd 0.0.0.0 > 5: gretun@eth0: <POINTOPOINT,NOARP,UP> mtu 8776 qdisc noqueue > link/gre 66.1.1.161 peer 66.1.2.161 > > root@den1tun01:/home/root $ ip tun > gre0: gre/ip remote any local any ttl inherit nopmtudisc > gretun: gre/ip remote 66.1.2.161 local 66.1.1.161 dev eth0 ttl 20 > > root@den1tun01:/home/root $ ifconfig > eth0 Link encap:Ethernet HWaddr 00:19:B9:DD:FF:D9 > inet addr:10.1.2.243 Bcast:10.1.3.255 Mask:255.255.254.0 > UP BROADCAST RUNNING MULTICAST MTU:8800 Metric:1 > RX packets:3357 errors:0 dropped:0 overruns:0 frame:0 > TX packets:484 errors:0 dropped:0 overruns:0 carrier:0 > collisions:0 txqueuelen:1000 > RX bytes:230757 (225.3 KiB) TX bytes:63937 (62.4 KiB) > Interrupt:169 Memory:f8000000-f8011100 > > eth0.2 Link encap:Ethernet HWaddr 00:19:B9:DD:FF:D9 > inet addr:66.1.1.161 Bcast:66.1.1.191 Mask:255.255.255.192 > UP BROADCAST RUNNING MULTICAST MTU:8800 Metric:1 > RX packets:950 errors:0 dropped:0 overruns:0 frame:0 > TX packets:20 errors:0 dropped:0 overruns:0 carrier:0 > collisions:0 txqueuelen:0 > RX bytes:43860 (42.8 KiB) TX bytes:1200 (1.1 KiB) > > gretun Link encap:UNSPEC HWaddr > 42-0B-33-A1-FF-C0-00-00-00-00-00-00-00-00-00-00 > inet addr:10.253.253.1 P-t-P:10.253.253.2 Mask:255.255.255.0 > UP POINTOPOINT RUNNING NOARP MTU:8776 Metric:1 > RX packets:0 errors:0 dropped:0 overruns:0 frame:0 > TX packets:7 errors:0 dropped:0 overruns:0 carrier:0 > collisions:0 txqueuelen:0 > RX bytes:0 (0.0 b) TX bytes:756 (756.0 b) > > gre0 Link encap:UNSPEC HWaddr > 00-00-00-00-FF-00-00-00-00-00-00-00-00-00-00-00 > UP RUNNING NOARP MTU:1476 Metric:1 > RX packets:0 errors:0 dropped:0 overruns:0 frame:0 > TX packets:0 errors:0 dropped:0 overruns:0 carrier:0 > collisions:0 txqueuelen:0 > RX bytes:0 (0.0 b) TX bytes:0 (0.0 b) > > lo Link encap:Local Loopback > inet addr:127.0.0.1 Mask:255.0.0.0 > UP LOOPBACK RUNNING MTU:16436 Metric:1 > RX packets:225 errors:0 dropped:0 overruns:0 frame:0 > TX packets:225 errors:0 dropped:0 overruns:0 carrier:0 > collisions:0 txqueuelen:0 > RX bytes:13271 (12.9 KiB) TX bytes:13271 (12.9 KiB) > > > I've also tried changing the destination for the route to the near end of > the private subnet and tried pinging various things on the tunnel subnet and > remote network to create "interesting traffic" to bring the tunnel up but > tcpdump still shows nothing. > > Then I noticed that ping does show an error count: > > [root@den1tun01 ~]# ping 10.253.253.2 > PING 10.253.253.2 (10.253.253.2) 56(84) bytes of data. >> From 10.253.253.1 icmp_seq=0 Destination Host Unreachable >> From 10.253.253.1 icmp_seq=1 Destination Host Unreachable > > --- 10.253.253.2 ping statistics --- > 2 packets transmitted, 0 received, +2 errors, 100% packet loss, time 1000ms > , pipe 2 > > I can ping the local end: 10.253.253.1, but the tunnel is still > non-functinoal. > > Thanks! > Greg > > _______________________________________________ > 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
