BBS:      TELESC.NET.BR
Assunto:  Re: Fmail and SMTP
De:       Wilfred van Velzen
Data:     Wed, 8 Apr 2026 13:15:37 +0200
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Hi Michiel,

On 2026-04-08 12:37:54, you wrote to me:

 MvdV> I did some experiments and found the following:

 MvdV> In windows there are two "names".

 MvdV> 1) The short one. This is the name entered when setting up the system. The
 MvdV> short name may only contain the characters a-z, A-Z, 0-9 and '-'. Dots are not
 MvdV> allowed. It is the name returned by gethostname().

 MvdV> 2) The full host name. There is an option in the windows configuration to
 MvdV> enter a domain. By default it is blank but one can enter someting like
 MvdV> "vlist.eu". This domain is appended to the short name to make the "full
 MvdV> computer name".

 MvdV> I tried changing the short computer name into fido.vlist.eu. Not accepted.
 MvdV> Then I left the short computer name as "Fido" and entered "vlist.eu" as the
 MvdV> DNS extension. That was accepted and the full computer name is now
 MvdV> "Fido.vlist.eu". *1)

 MvdV> I tied sending the test message again to Tommi's SMTP server but got the same
 MvdV> error. So apparently the short name is still used is the HELO.

What does the hostname command show in this situation?

 MvdV> Two suggestions:

 MvdV> 1) Find a "full name" equivalent for gethostname().  getfullhost?

gethostname() is indeed probably not the best way to get a fqdn. But I'll have to investigate if there is a better function to get this from the OS.

 MvdV> 2) Take the part after the '@' from the e-mail adres configured in
 MvdV> Fmail and append that to the name recovered by gethostname() for use
 MvdV> in the HELO.

Also not perfect, because the sender email address, doesn't necessarily contain the hostname of the sending machine.

The only propper sollution is to make this a configuration item...

 MvdV> *1) I already found some undesirable side effects of this change,
 MvdV> but that's another story.

...

Bye, Wilfred.

--- FMail-lnx64 2.3.2.6-B20251227
 * Origin: FMail development HQ (2:280/464)

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