Remote OS Detection

pankaj_it09 has asked for the wisdom of the Perl Monks concerning the following question:

Replies are listed 'Best First'.
Re: Remote OS Detection by marto (Cardinal) on Apr 07, 2010 at 08:52 UTC
If the remote host has perl you login (via ssh) and use `$OSNAME` or `$^O`, see perlvar. `man uname` on a *nix host may be what you're looking for.	[reply] [d/l] [select]
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Re: Remote OS Detection by ZlR (Chaplain) on Apr 07, 2010 at 12:09 UTC
I would use nmap to do that.	[reply]
Re^2: Remote OS Detection by marto (Cardinal) on Apr 07, 2010 at 12:12 UTC
This may not be the best approach, since they have legitimate access to the systems in question. See A practical approach for defeating Nmap OS-Fingerprinting.	[reply]
Re^3: Remote OS Detection by ZlR (Chaplain) on Apr 07, 2010 at 12:24 UTC
What a fascinating article ! Modifying the kernel's tcp stack to fool nmap, that's some level of extremism i had not seen before :)	[reply]
Re^4: Remote OS Detection by marto (Cardinal) on Apr 07, 2010 at 12:29 UTC
Re: Remote OS Detection by Anonymous Monk on Apr 07, 2010 at 08:52 UTC
?? os type How to determine the OS type in a logon script , OSType	[reply]