[plug] checking for existence of an application

[James Devenish]

In message <sf33f7b8.056 at mmtnetworks.com.au>
on Fri, Aug 08, 2003 at 07:19:16PM +0800, Jon  Miller wrote:
> >>> zombie at penguincare.com.au 6:29:48 PM 8/08/2003 >>>
> On Fri, 8 Aug 2003, quoth Jon  Miller:
> 
> > Is there a way to check for the existence of the mail program in use.
> 
> Telnet to localhost on port 25 and read the banner.
> (unless someone's deliberately disguised it)
[...]
> okay, but that would put you in an interactive mode in which case you
> need to exit this session.

Firstly, you can do this from a script. There is no need for
"interactive mode" (whatever that might mean).

Secondly, MTAs don't necessarily show their name in their SMTP 220
responses (which is what Matt seems to be thinking of). This is not
necessarily about "concealment" of anything, it is just that some SMTP
servers are not very verbose and instead tell you the host name, or
because an admin wanted to put something "prettier" in there. Sendmail
and Exim, however, will usually identify themselves verbosely.