extended traceroute to check port being block

[maher]

hi there,

Our customer tells that somewhere in the internet clould in our network is bloking the port. Most of the time, if the customer complain, i will use the telnet technique which is to indicates that the firewall is not blocking:

telnet www.webserver.com 80 /source-interface fa0/0

However, ne of my customer shown this output from his router:

router#trace

Protocol [ip]:

Target IP address: 192.168.100.1

Source address:

Numeric display [n]:

Timeout in seconds [3]:

Probe count [3]:

Minimum Time to Live [1]:

Maximum Time to Live [30]:

Port Number [33434]: 137

Loose, Strict, Record, Timestamp, Verbose[none]:

Type escape sequence to abort.

Tracing the route to 192.168.100.1

1 202.183.1.161 !A * !A

What makes me confuse is that from the port number by default 33434 but it changed to 137. Does it means it will check the particular port along the hop?

Any documentation regarding to understand the output such above?

Thanks.

maher

[rlcarr · Accepted solution]

Here is a link that will help you...

http://www.cisco.com/univercd/cc/td/doc/product/software/ios123/123tcr/123tfr/cfrgt_12.htm#wp1058298

When you use port numbers with Telnet, the port is a TCP port.

When you use port numbers with Traceroute, the port is a UDP port.

And yes the !A means that an access-list is blocking.

Hope this helps,

~ron

[tushar47 · Accepted solution]

Dear sir,

137 port is a virus port. So most of the Network Admin. block that port in their router.

Regards,

Ashu