[Info-vax] SMTP chunk sizes

[Rich Jordan]

On Monday, March 23, 2015 at 6:39:55 PM UTC-5, Stephen Hoffman wrote:
> 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.
> 
> 
> -- 
> Pure Personal Opinion | HoffmanLabs LLC

Hoff,
     thanks.  If I had time I'd play with options but as per usual, got to squeeze this in as can where can with equipment on hand.  The server has room, IIS SMTP was already set up to allow their phones to do authenticated email.

     Using the windows server as smarthost is fine for small mail so far.  However I just sent the same email message that would take 15-20 minutes to get to GMAIL, and would die going to MS in 10 minutes, and it took over 75 minutes to send from the Alpha to the PC (on the same LAN...).  That was the 10.8MB body message (all text).  The same text file attached (and so uuencoded) is at 78 minutes now.

     Once it got to the windows server it appeared to take about 2 minutes to get to me, so thats good, but we'll have to see if anything can be done about the intersystem pokiness.  I'll try and get a packet trace tomorrow.

     And I think the scanners and PDF generators can just send direct to the PC server too.  We'll see.

     Thanks all for the info.

Rich