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by: Bernard Teo








Creative Commons License

Copyright © 2003-2012
Bernard Teo
Some Rights Reserved.

Mon 03 Jan 2005

I get a breakthrough

Category : Technology/spamblocks.txt

We know for a fact that some mail servers are rather picky. They will reject mail coming from a dynamically assigned IP address, or one without a domain name, or follow any some other rule.

I've been wondering why my mail from cutedgesystems.com (which is on a dynamic IP address) sometimes get through to the people at Apple Singapore and sometimes they don't (when Apple's servers' decide that it could be spam).

It's puzzled me for over a year - i.e., what has changed in my configuration that makes those servers decide one way or the other, because obviously I want my mail to get through all the time.

I rebooted our server today and realised that I couldn't send mail out to Leon Chen at Apple anymore, even though I've been able to do so for months now. So something has changed.

I dug around and found the answer - it's the DNS server. I've been playing around with setting up a DNS server, on and off, over the year. Turning the DNS server off causes the mail to be bounced back from a picky server. Turning it back on gets the mail through.

If there is a DNS service running on our local network when the mail server starts up, it'll be able to correctly discover its own domain name. (Otherwise it knows itself as, say, roadsteadserver.local). Seems like, when it knows that it should be cutedgesystems.com, it'll be able to send mail out to other servers without getting bounced. (Or some such explanation.)

I don't know if I really understand what is happening but the moral of the story is - it's good to be able to run your own DNS service.

I've got a version of Postfix Enabler (in Obj-C) that will work with the next revision of our favourite OS - except that it leaks memory. Lots of it, I'm sure, until I figure out how all these retain and release stuff works. (Mike Beam's article at O'Reilly is a great starting point.) It ought to be known as Postfix Configurator or something because it won't be doing much enabling anymore.

Posted at 5:31PM UTC | permalink

The Sun Breaks Through

Category : Commentary/newbeginnings.txt

After four days of torrential rain, we greet the sun for the first time in the New Year. Like the sky has been crying buckets, for the trail of devastation left behind in Asia.

Posted at 10:37AM UTC | permalink

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Services running on this server, a Mac Mini running Mac OS X 10.9.2 Mavericks:

  • Apache 2 Web Server
  • Postfix Mail Server
  • Dovecot IMAP Server
  • Fetchmail
  • SpamBayes Spam Filter
  • Procmail
  • BIND DNS Server
  • DNS Agent
  • WebDAV Server
  • VPN Server
  • PHP-based weblog
  • MySQL database
  • PostgreSQL database

all set up using MailServe, WebMon, DNS Enabler, DNS Agent, VPN Enabler, Liya and our SQL installers, all on Mavericks.