# ISPs and content blocking

## audiodef

What's a good way to verify whether my ISP blocks certain things (other than calling them and talking with people who don't know a bit from a byte)? I'm trying to test Bittorrent with some files I've created from my music (mine meaning I wrote it), but Bittorrent is stopped at "check for firewall". I don't have a firewall set up here, so it's not me.

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## cach0rr0

you have access to an external host? 

My knee-jerk reaction would be to ssh to an external host and:

```

nmap -sT -p<portnum> -P0 -vv x.x.x.x
```

where x.x.x.x is your IP. 

Rather than testing with the torrent client, probably easiest to just set up a netcat listener on that port.

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## krinn

http://www.dyndns.com/support/tools/openport.html

as cach0rr0 suggest, just you don't have to find an external host

They are tons of website if you google for "testing open port", i just provide dyndns.com one that is not really complete, but a "trust" url.

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## cach0rr0

if you're desperate, I just threw this up

not pretty, only did a very quick job of making sure I'm not opening myself up completely:

http://whitehathouston.com/nmap.php?port=1723

(adjust the port accordingly - i provide no frontend! and of course it only does -sT, since the command is run as 'apache' user the other options are limited. )

Just fires off nmap at whatever IP you're connecting from, on the port you specify as the cmd-line argument as seen above. There are other ways to do this (e.g. with php sockets), but that's more convoluted, and where I trust nmap to always tell me the truth, I don't with php.

If you're ssh'd in, just curl it, the output is still legible (e.g. #curl http://whitehathouston.com/nmap.php?port=22)

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## energyman76b

http://www.heise.de/security/dienste/Netzwerkcheck-2114.html

scans all the ports you want it to scan on.

Just scroll down to Tests and click on 'eigener Test'.

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## audiodef

I think Bittorrent and Vuze got a delayed start, as my download seems to have worked if I left it alone for a while. But I'll keep these tips handy in case I need to check. Thanks!   :Cool: 

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