Re: Fwd: Balsa default mail submission on TCP port 587, not port 25 [major@satx.rr.com]

[Brian Stafford <brian stafford uklinux net>]

On 2001.07.09 18:35:20 +0100 balsa@microwave.com wrote:

> > > Ok, perhaps not a 'port' field, but some indication of what a defaut value
> > > is. Perhaps if someone enters just "smtp.foobar.com", it should
> > > automatically add (not just internally, but in the displayed setting as
> > > well), the :587 (or whatever the official designator is)..
> >
> > I disagree.  libESMTP, and hence Balsa, does the correct thing with a bare
> > domain name.
> 
> It may very well 'do' the correct thing, but it doesnt take much care to
> *show* what it is doing.

Well, the application just passes the string to the libESMTP API which parses
it as it sees fit.  As long as the application does not make assumptions
about the syntax of this, it is easy to extend it in the future without breaking
the application. I consider that it is enough to document the syntax somewhere.

One possible future syntax extension might be to accept something like
"|/usr/sbin/sendmail -bs"; its sort of hard to see how to explain the default
port number on that one.  The situation is bad if the application nails
on ":587" to the end of the string the user specifies.  Worse still if it
refuses to pass the string to the libESMTP API or crashes because it can't
parse the syntax.

> > > I can think of no other MUA that both defaults to what is (irt current
> > > deployment) a non-standard port,
> >
> > Er, sorry but RFC 2476 states that 587 is the standard port for mail
> > *submission*.  Port 25 is the standard port for mail *relay*.  Like it or
> > not these are different protocols, hence the different port numbers.
> > RFC 2476 is s standards track RFC so you are wrong about the non standard
bit.
> 
> Ok, it may be the current _specified_ standard, but it is deployed almost
> nowhere. (Probably since very few current 'popular' (eg Micro$oft)  MUAs
> have any idea what it is yet)

So what?  Are you saying that the open source community must wait for
commercial software to adopt a standard before it does so for itself?
The reality is that RFC 2476 is only about 18 months old.  However
recent releases of MTAs are starting to adopt it (sendmail comes to mind,
it hasn't waited for Netscape or MS to act first).

> > Um... read Balsa's docs or the README file.  Both explain the default.
> 
> 'immediate', eg on the config dialog. Not buried in documentation.

Provide a patch to put the info in a tool tip or something if you
feel that strongly about it.

> > When it comes to adopting new protocols or standards, someone has to take
> > the lead.  The argument that other programs don't do it yet hardly stands
> > up, especially considering that there are no issues with interoperability.
> 
> I dont have a problem with balsa defaulting to 587, just that it doesnt
> make it very apparent that it is doing so.

Would you have a problem with the default being port 25 without explanation?
I doubt you'd have thought to even raise the point, despite the fact that SMTP
on port 25 was designed for mail relay and was never intended for mail
submission (hence RFC 2476).

The problem here is people "just know" that SMTP happens to be on port 25
therefore that is where their MUA should look for a server.  The plain fact
is that such folk knowledge is wrong.  By implementing the correct standard
people are forced to confront the issue and configure things properly or,
at worst, to suit their local situation.  If they actually read the
documentation first they might not even have to complain about this on
the list.

Brian Stafford