Service: port to name

carric has asked for the wisdom of the Perl Monks concerning the following question:

Gentlemen,

I have been looking through the nodes for some mention of this, and I can't seem to find one.

I want to be able to translate a list of port numbers into their respective service names. e.g.:

tcp21: ftp
tcp22: ssh
tcp23: telnet
udp53: named
etc...

Anyone know how to do this? Thanks in advance!!

***UPDATE***

The function I was looking for appears to be getsrvbyport(), but the docs are a bit sparse.

Comment on Service: port to name

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Re: Service: port to name by BazB (Priest) on Mar 21, 2004 at 18:20 UTC
Net::IANA::PortNumbers or the standard Net::servent. If the information in this post is inaccurate, or just plain wrong, don't just downvote - please post explaining what's wrong. That way everyone learns.	[reply]
Re: Re: Service: port to name by carric (Beadle) on Mar 21, 2004 at 18:37 UTC
BTW, when you go to install this module, it is called Net::IANA::PortNumbers, BUT though the CPAN module, you have to call it New::IANA::PortNumber. `%cpan>install Net::Install::PortNumber` [download]	[reply] [d/l]
Re: Re: Service: port to name by carric (Beadle) on Mar 21, 2004 at 18:30 UTC
sweet! I think that might do it.	[reply]
Re: Service: port to name by chip (Curate) on Mar 21, 2004 at 22:42 UTC
C'mon guys, give me a hard one. It's a core language feature: `getservbyport()`. `print scalar getservbyport(23,"tcp"),"\n" telnet` [download] -- Chip Salzenberg, Free-Floating Agent of Chaos	[reply] [d/l] [select]
Re: Service: port to name by jeffa (Bishop) on Mar 21, 2004 at 18:13 UTC
If you don't mind building up a hash into memory every time you run it, and you don't mind not only having to hardcode the service, but also having to use the form '21/tcp' instead of '21tcp', then the following code should do the job: `perl -lane'$h{$F[1]}=$F[0]}{print $h{"21/tcp"}' /etc/services` [download] But then again, it looks like i just reinvented a wheel called 'grep'. ;) I would be surprised if there is not an existing CPAN module for this task ... i don't know of one off hand ... jeffa L-LL-L--L-LL-L--L-LL-L-- -R--R-RR-R--R-RR-R--R-RR B--B--B--B--B--B--B--B-- H---H---H---H---H---H--- (the triplet paradiddle with high-hat)	[reply] [d/l]
Re: Service: port to name by pbeckingham (Parson) on Mar 21, 2004 at 18:07 UTC
Try `cat /etc/services`.	[reply] [d/l]
Re: Service: port to name by The Mad Hatter (Priest) on Mar 21, 2004 at 18:17 UTC
Here's some code that generates a hash similar to Jeffa's, but it's not a one liner. Meant for use in another program... Read more... (980 Bytes)	[reply] [d/l]