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Hi all, |
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|
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In Bash /dev/tcp/host/port can be used to write to a TCP socket. This |
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works nicely so I was very curious whether it would work the other way |
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too: is it possible to have a Bash script listen on a particular port |
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as if it were a server? I couldn't find anything in the Bash manual |
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about it. Google does find a few examples but they all use nc. But |
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that's cheating! ;-) Is it possible with just Bash, no extra tools? |
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(If yes, please enlighten me as to how, obviously I could not get it |
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to work.) |
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|
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On a related note, I read some comments about Debian having /dev/tcp |
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disabled in Bash because of security concerns. Would someone |
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knowledgeable about security be able to comment on that? It doesn't |
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make much sense to me. I mean, any Perl, Python, Ruby, etcetera script |
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can write to a socket. Even Debian (with every option deselected) |
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comes installed with Perl. (Yes, I installed Debian just to find out!) |
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:-) So why should /dev/tcp in Bash be deemed such a security risk? |
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|
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Cheers, |
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Hilco |
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|
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P.S. For the curious: |
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#!/bin/bash |
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exec 3<>/dev/tcp/www.google.ca/80 |
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echo -ne "GET / HTTP/1.1\r\n">&3 |
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echo -ne "Host: www.google.ca\r\n">&3 |
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echo -ne "Connection: close\r\n">&3 |
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echo -ne "\r\n">&3 |
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cat <&3 |
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