Strange routing behaviour

[Daniel Neeves]

Can anyone answer this strange issue, A traceroute command to any address always uses lan9:1 :

Routing Table

netstat -rn
Routing tables
Destination Gateway Flags Refs Interface Pmtu
127.0.0.1 127.0.0.1 UH 0 lo0 4136
192.168.132.60 192.168.132.60 UH 0 lan1:2 4136
192.168.132.61 192.168.132.61 UH 0 lan1:1 4136
192.168.133.26 192.168.133.26 UH 0 lan0 4136
192.168.132.20 192.168.132.20 UH 0 lan1 4136
192.168.130.20 192.168.130.20 UH 0 lan9 4136
192.168.130.249 192.168.130.249 UH 0 lan9:1 4136
192.168.133.16 192.168.133.26 U 2 lan0 1500
192.168.132.0 192.168.132.20 U 4 lan1 1500
192.168.132.0 192.168.132.60 U 4 lan1:2 1500
192.168.132.0 192.168.132.61 U 4 lan1:1 1500
192.168.130.0 192.168.130.20 U 3 lan9 1500
192.168.130.0 192.168.130.249 U 3 lan9:1 1500
10.98.0.160 192.168.132.5 UG 0 lan1 0
10.49.56.128 192.168.132.5 UG 0 lan1 0
10.97.8.0 192.168.132.5 UG 0 lan1 0
10.49.63.0 192.168.132.5 UG 0 lan1 0
10.49.107.0 192.168.132.5 UG 0 lan1 0
192.168.131.0 192.168.132.5 UG 0 lan1 0
192.168.132.0 192.168.132.5 UG 0 lan1 0
127.0.0.0 127.0.0.1 U 0 lo0 0
default 192.168.130.5 UG 0 lan9 0

NIC Config

lan0: flags=843
inet 192.168.133.26 netmask fffffff0 broadcast 192.168.133.31
lan1: flags=843
inet 192.168.132.20 netmask ffffffc0 broadcast 192.168.132.63
lan5: flags=842
inet 0.0.0.0 netmask 0
lan9: flags=1843
inet 192.168.130.20 netmask ffffff00 broadcast 192.168.130.255
lan10: flags=842
inet 0.0.0.0 netmask 0
lan1:1: flags=843
inet 192.168.132.61 netmask ffffffc0 broadcast 192.168.132.63
lan9:1: flags=1843
inet 192.168.130.249 netmask ffffff00 broadcast 192.168.130.255

Example traceroutes

traceroute 127.0.0.1
traceroute: Warning: Multiple interfaces found; using 192.168.130.249 @ lan9:1
traceroute to 127.0.0.1 (127.0.0.1), 30 hops max, 40 byte packets
1 pkg_mst1 (192.168.130.249) 0.286 ms 0.086 ms 0.052 ms

traceroute 10.49.56.128
traceroute: Warning: Multiple interfaces found; using 192.168.130.249 @ lan9:1
traceroute to 10.49.56.128 (10.49.56.128), 30 hops max, 40 byte packets


In fact any traceroute uses lan9:1 ?

[Tim Nelson]

for multihomed hosts you will need to specify which interface to use with traceroute.

traceroute -i lan0 xxx.xxx.xxx.xxx

man traceroute for more info.

[Sandman!]

The routing table entry below looks bad & I'm not sure how traceroute is even able to trace it.

> 10.49.56.128 192.168.132.5 UG 0 lan1 0 <

should be

10.49.56.128 192.168.132.5 UGH 0 lan1 0

Is that how it should be?

[Daniel Neeves]

Thanks for the comments so far, I should explain its not really a traceroute question ( I Know about the -i option) the question is why is every traceroute I've tested using lan9:1 ? If theres is another way I can interrogate the routing without traceroute let me know.

[SGUX]

Daniel,
there are several threads about this traceroute issue. Bottomline is that from HP-UX 11.11 traceroute is using, without the -i option, the first NIC in the netstat -rn output. As far as i read the only way to get around this is using -i .

[Daniel Neeves]

Thanks for the info so far, So in the example I posted above why does traceroute use lan9:1 when routing to 10.49.56.128 surely it should use lan1 as per the routing table?

[Sandman!]

Would help to have more information before we try to figure this one out. Please post the output of the below commands here:

# netstat -rnv
# netstat -in

[Daniel Neeves]

By all means, here is the info requested below:

netstat -rnv
Routing tables
Dest/Netmask Gateway Flags Refs Interface Pmtu
127.0.0.1/255.255.255.255 127.0.0.1 UH 0 lo0 4136
192.168.132.62/255.255.255.255 192.168.132.62 UH 0 lan1:1 4136
192.168.132.15/255.255.255.255 192.168.132.15 UH 0 lan1 4136
192.168.130.15/255.255.255.255 192.168.130.15 UH 0 lan9 4136
192.168.133.10/255.255.255.255 192.168.133.10 UH 0 lan0 4136
192.168.133.0/255.255.255.240 192.168.133.10 U 2 lan0 1500
192.168.132.0/255.255.255.192 192.168.132.15 U 3 lan1 1500
192.168.132.0/255.255.255.192 192.168.132.62 U 3 lan1:1 1500
192.168.130.0/255.255.255.0 192.168.130.15 U 2 lan9 1500
10.98.0.160/255.255.255.224 192.168.132.5 UG 0 lan1 0
10.49.56.128/255.255.255.192 192.168.132.5 UG 0 lan1 0
10.49.63.0/255.255.255.0 192.168.132.5 UG 0 lan1 0
10.49.107.0/255.255.255.0 192.168.132.5 UG 0 lan1 0
10.97.8.0/255.255.255.0 192.168.132.5 UG 0 lan1 0
192.168.131.0/255.255.255.0 192.168.132.5 UG 0 lan1 0
192.168.132.0/255.255.255.0 192.168.132.5 UG 0 lan1 0
127.0.0.0/255.0.0.0 127.0.0.1 U 0 lo0 0
default/0.0.0.0 192.168.130.5 UG 0 lan9 0

netstat -in
Name Mtu Network Address Ipkts Ierrs Opkts Oerrs Coll
lan10* 1500 none none 0 0 0 0 0
lan1:1 1500 192.168.132.0 192.168.132.62 20103106 0 1242327 0 0
lan9 1500 192.168.130.0 192.168.130.15 450157211 0 646210218 0 0
lan1 1500 192.168.132.0 192.168.132.15 3239289209 0 2898401189 0 0
lan0 1500 192.168.133.0 192.168.133.10 220922669 0 229986530 0 69361
lo0 4136 127.0.0.0 127.0.0.1 3571338416 0 3571340776 0 0
lan5* 1500 none none 0 0 0 0 0

[Sandman!]

Hmmm...what happened to the routing table entry for lan9:1? Seems to have disappeared. Did you delete it? Try the traceroute now without the lan9:1 entry.

~thanks

[Daniel Neeves]

Sorry my mistake, netstat were from the wrong host, correct ones below :

netstat -rnv

Routing tables
Dest/Netmask Gateway Flags Refs Interface Pmtu
127.0.0.1/255.255.255.255 127.0.0.1 UH 0 lo0 4136
192.168.132.60/255.255.255.255 192.168.132.60 UH 0 lan1:2 4136
192.168.132.61/255.255.255.255 192.168.132.61 UH 0 lan1:1 4136
192.168.133.26/255.255.255.255 192.168.133.26 UH 0 lan0 4136
192.168.132.20/255.255.255.255 192.168.132.20 UH 0 lan1 4136
192.168.130.20/255.255.255.255 192.168.130.20 UH 0 lan9 4136
192.168.130.249/255.255.255.255 192.168.130.249 UH 0 lan9:1 4136
192.168.133.16/255.255.255.240 192.168.133.26 U 2 lan0 1500
192.168.132.0/255.255.255.192 192.168.132.20 U 4 lan1 1500
192.168.132.0/255.255.255.192 192.168.132.60 U 4 lan1:2 1500
192.168.132.0/255.255.255.192 192.168.132.61 U 4 lan1:1 1500
192.168.130.0/255.255.255.0 192.168.130.20 U 3 lan9 1500
192.168.130.0/255.255.255.0 192.168.130.249 U 3 lan9:1 1500
10.98.0.160/255.255.255.224 192.168.132.5 UG 0 lan1 0
10.49.56.128/255.255.255.192 192.168.132.5 UG 0 lan1 0
10.97.8.0/255.255.255.0 192.168.132.5 UG 0 lan1 0
10.49.63.0/255.255.255.0 192.168.132.5 UG 0 lan1 0
10.49.107.0/255.255.255.0 192.168.132.5 UG 0 lan1 0
192.168.131.0/255.255.255.0 192.168.132.5 UG 0 lan1 0
192.168.132.0/255.255.255.0 192.168.132.5 UG 0 lan1 0
127.0.0.0/255.0.0.0 127.0.0.1 U 0 lo0 0
default/0.0.0.0 192.168.130.5 UG 0 lan9 0

netstat -in

Name Mtu Network Address Ipkts Ierrs Opkts Oerrs Coll
lan10* 1500 none none 0 0 0 0 0
lan9:1 1500 192.168.130.0 192.168.130.249 93892136 0 1706697 0 0
lan1:1 1500 192.168.132.0 192.168.132.61 1611559619 0 763962466 0 0
lan9 1500 192.168.130.0 192.168.130.20 3593619389 0 3160850173 0 0
lan1 1500 192.168.132.0 192.168.132.20 326741264 0 1324731539 0 0
lan0 1500 192.168.133.16 192.168.133.26 15306837 0 24285248 0 22843
lo0 4136 127.0.0.0 127.0.0.1 1706841122 0 1706841399 0 0
lan1:2 1500 192.168.132.0 192.168.132.60 762967097 0 546240335 0 0
lan5* 1500 none none 0 0 0 0 0