[Info-vax] SMTP chunk sizes

[Stephen Hoffman]

On 2015-03-23 21:39:29 +0000, Rich Jordan said:

> 
>   Process is out, for the same reason that PMDF, or an exchange server 
> is out.  Zero budget.

Got old hardware?

>      The ISP relay server is being accessed as documented by them; if 
> its not kicking back the 'busy' errors constantly because its actually 
> busy, I thought it might just greylist everybody on its allow  list 
> (based on IP address; only customer IPs can use it to relay).  However 
> I tried 5, 15, 30, and 60 minute delays and kept getting busy errors so 
> its just not going to work.  The ISP, though they gave me the initial 
> info and assured that unauthenticated access on port 25 would work (I 
> do that from home with some equipment alerts via Comcast), they have 
> not responded since to the trouble reports.

Port 25 is seldom authenticated.  Source IP addresses for the incoming 
connections often are checked for proper DNS and blacklists.  It's 
certainly conceivable that the ISP is greylisting everything always, 
but that's less common and it can cause legitimate mail to be dropped — 
at least one of the major mail ISPs has a gazillion outbound servers, 
and was seemingly much more willing to just drop mail when the 
administrator of the receiving server was mildly aggressive with its 
greylisting configuration.

> We have IIS and its SMTP server on a PC box with some resources to 
> spare so that's where we're going for smarthost.

Ayup.  A spare x86-class box where I'd go, though I'd usually go with 
Linux and Postfix, or with BSD and OpenSMTPD.   Or OS X with Server.app 
installed, if that's the sort of x86 box available for use.  (Ponders 
whether "a PC box" will still be called that around here, once an x86 
version of OpenVMS ships.  But I digress.)  Windows Server with 
Exchange Server will work, too.  I'm not familiar with the IIS SMTP 
service, but... Okay.   Still tempted to haul over Lamson for a look, 
but having a BSD box is

> Shortest interval to ACK from Microsoft seen was 233ms, average was 
> probably around 250ms, there were frequent 300-320ms intervals.  MS 
> says those longer delays are deliberate.

The OpenVMS TCP/IP Services SMTP server is stale.  Alas, there's also 
no easy way to disable and bypass it either, if you are using software 
that is based on the local MAIL.EXE client or on the Callable Mail API.


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