Traceroute failing

[Tonya Underwood]

Believe may be issue with routing?

# netstat -nrv
Routing tables
Dest/Netmask Gateway Flags Refs Use Interface Pmtu
127.0.0.1/255.255.255.255
127.0.0.1 UH 0 639135 lo0 4136
155.125.45.240/255.255.255.255
155.125.45.240 UH 0 10587373 lan0 4136
143.5.243.67/255.255.255.255
143.5.243.67 UH 0 6727 lan1 4136
143.5.243.64/255.255.255.224
143.5.243.67 U 2 0 lan1 1500
155.125.45.0/255.255.255.0
155.125.45.240 U 2 0 lan0 1500
155.125.45.0/255.255.255.0
155.125.45.1 UG 0 0 lan0 1500
192.44.190.0/255.255.255.0
155.125.45.1 UG 0 0 lan0 1500
127.0.0.0/255.0.0.0 127.0.0.1 U 0 0 lo0 4136
default/0.0.0.0 143.5.243.66 UG 0 0 lan1 1500

# traceroute bdhp4383
traceroute to bdhp4383.na.pg.com (155.125.75.85), 30 hops max, 20 byte packets
1 * * *
2 * * *
3 * * *
4 * * *
5 * * *
6 * * *
7 * * *
8 * * *
9 * * *
10 * * *
11 * * *
12 * * *
13 * * *
14 * * *
15 * *
...

traceroute fails when not on subnet...

Thanks,
Tonya

[Jeff Schussele]

Hi Tonya,

You need to supply either

-i lanX
where X=lan instance

or

-s xxx.xxx.xxx.xxx
where that is the source IP to start the traceroute from.

If you don't specify which I/F to use it's liable to pick the wrong one.

HTH,
Jeff

[Tonya Underwood]

[root@bdhp4226:/root]
# traceroute -s 155.125.45.240 bdhp4383
traceroute to bdhp4383.na.pg.com (155.125.75.85) from 155.125.45.240, 30 hops max, 20 byte packets
1 bdc3css268.na.pg.com (143.5.254.4) 1 ms 0 ms 0 ms
2 143.5.254.2 (143.5.254.2) 0 ms 0 ms 0 ms
3 bdhp4383.na.pg.com (155.125.75.85) 0 ms 0 ms 0 ms

[root@bdhp4226:/root]
# traceroute -s 143.5.243.67 bdhp4383
traceroute to bdhp4383.na.pg.com (155.125.75.85) from 143.5.243.67, 30 hops max, 20 byte packets
1 *


Can I not manipulate my configuration to allow for traceroute from any interface?

[Jeff Schussele]

Hi (again) Tonya,

No - not really.
But what you can do is create aliases to do it for you:

alias traceroute1='traceroute -i lan1'
alias traceroute2='traceroute -i lan2'

These can be placed in a .alias file & sourced at login.

Rgds,
Jeff

[Sridhar Bhaskarla · Accepted solution]

Tonya,

The real problem is that you don't have a route specified for the destination 155.125.75.85. Traceroute with 11i in this situation can mislead you.

You may need to add a static route as this destination cannot be reached through your default gateway (I believe your original problem is about not able to reach the destination).

If 155.125.45.1 is your gateway in 155.125.45 subnet, then try

route add net 155.125.75.0 netmask 255.255.255.0 155.125.45.1 1

You may be able to broaden the route by specifying a bigger subnet mask but you will need to check with your network folks on the route setup. They may advise you with the correct route statement.

-Sri