Solved: traceroute using tcp on a specific port?

On Wednesday, Feb 4th 2004 at 16:17 -0500, quoth Steven W. Orr:

=>My home linux system had a whole lot of connectivity problems a few days 
=>ago. One of the problems was that all of a sudden people who tried to 
=>connect to my sendmail server got connection refused. 
=>
=>I knew that the problem was not related to anything going on at my end. My 
=>server was not getting any packets (seen via ethereal). I called my ISP 
=>(RCN) who insisted that they were not blocking my port 25. (I pay extra 
=>for them to not block me.)
=>
=>And yet when I went over to another machine outside of RCN and tried to 
=>telnet to my 25 I would in fact get connection refused.
=>
=>To add to the confusion, a friend told me that a backbone had just gone 
=>bankrupt and the whole world was trying to figure out how to reroute 
=>packets. The result was that packets were taking more hops to get where 
=>they wanted to go.
=>
=>So what I am looking for is a tool that can tell me just where along the 
=>path my packets were getting refused. How can I tell if it was RCN or 
=>someone even before it got to RCN.
=>
=>(The problem clearup up after >5 hours.)
=>
=>Thanks guys.

The winner is tcptraceroute. Something that everyone should keep in their 
toolbox. Lance and a couple of other people pointed to it.

Thanks everyone. :-)

On Wednesday, Feb 4th 2004, quoth Lance Levsen <lance-8fVGZEMlguYsA/[email protected]>, :

=>http://michael.toren.net/code/tcptraceroute/
=>
=>It's in Debian testing, don't know about the other distros.
=>
=>Works just like traceroute except it uses a tcp port.
=>
=>$> tcptraceroute mail.blah.com 25
=>
=>Cheers,
=>lance

-- 
Time flies like the wind. Fruit flies like a banana. Stranger things have  .0.
happened but none stranger than this. Does your driver's license say Organ ..0
Donor?Black holes are where God divided by zero. Listen to me! We are all- 000
individuals! What if this weren't a hypothetical question?
steveo at syslang.net
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