Paul McCormack’s Web Site

Postgrey is a very simple, but apparently effective spam fighting tool that looks at an incoming mail message as it is sent to the server. Before accepting the full mail, Postgrey checks to see if the combination of the source, sender and recipient are recently known. If they are then Postgrey accepts the mail.

If they are not, the mail is temporarily rejected, that is grey-listed (hence the name Postgrey) as opposed to black-listed (always blocked) or white-listed (always allowed). Legitimate mail servers will retry after five minutes and the mail will then be accepted. After receiving 5 messages in a 35-day period the mails become trusted (added to the white-list) and are no longer delayed.

The idea is that spammers can’t be bothered to waste time trying to resend messages so they give up, knowing that people running Postgrey will also be running other spam filters, so their messages will probably be trapped anyway.

The advantages for people running Postgrey are

1. Spam is rejected before it is fully received, saving network capacity and usage allowances
2. The overhead on the spam filter is massively reduced as less is accepted and filtered
3. Users are less likely to get spam as the server has another level of protection

I thought that I had been running Postgrey for a few months, but I have just realised that I had not set it up properly and it was being bypassed. I have now rectified this and can see that it is working properly.

The only down-side is that mail will be delayed for at least 5 minutes from senders that are not yet on the white-list, but I can live with that if you can.

I’ve been busy researching how to securely send e-mails from this web site and I have found a clever little plugin that does just what I want.

The Contact page has a form that will be e-mailed to me when correctly submitted. It uses spam protection to check your name and e-mail address against known spammers and also a check that you are human by typing in characters from an image.

It’s a shame that it is not safe to just post an e-mail address on a web site, but that’s the nature of the Internet.

If you know my e-mail (and it’s not hard to guess if you are already on this site - here’s a clue: paul at …) then you can also get in touch via instant messenger. My e-mail address is also my ID for Jabber and MSN Messenger.

The same details should also work for direct VoIP calling if you have a VoIP provider that allows you to call direct. No surprises that BT Openworld is not one of these. You could try Ekiga.net as a free alternative.

I have UK and Australian phone numbers - drop me an e-mail or IM for details.

Talk to you soon!

I have been using VoIP phones for some time now and have found the quality and reliability to be excellent. I was previously using Skype, but I was frustrated with the frequent drop-outs and the lack of updates on Linux.

Asterisk has been out for a long time, but I hadn’t had time to look into it. I was happy enough with my Linksys SPA-3102 which I had set up with a clever dial plan so that any international calls were routed out to a UK VoIP provider, but all Australian calls would dial out over the POTS Optus line.

There were a couple of problems with this set up. The main one being that every so often the SPA-3102 would throw a tantrum and refuse to connect to the UK VoIP provider. This was the push that I needed to look further into Asterisk.

After a couple of weeks of playing around (and getting into trouble from Deborah as a result), I now have a great system that allows me to make and receive calls. Genius.

OK, so it does a bit more than that thankfully. The following is a list of the features that I have enabled:

• Our Nokia E65 phones connect to Asterisk via Wireless LAN when we enter the house and become “extensions” of the home phone system
• The SPA-3102 answers incoming Optus calls and passes them to Asterisk to handle
• After 10pm, the calls are screened to check if they are urgent. If they are, the caller presses 9 to be connected otherwise they press 1 and leave us a message
• All phones, including mobiles ring on an incoming call
• The UK VoIP calls are also handled by Asterisk
• Outbound calls are routed via choice of UK or Australian VoIP providers for least cost routing (I found that MyNetFone (AU) was cheaper than SipGate (UK) for UK land line calls)
• Speed Dialling from any phone (including mobiles) i.e. *0LEE (*0533) calls Lee

I am still to get the incoming caller ID to work. So far, the SPA-3102 recognises the CID but does not pass it to the Asterisk server. Once I get this working, then I will be able to have rules based on incoming caller. For example, when I call home via my mobile I will get a custom message that will allow me to do onward dialling to call the UK amongst other things.

Now all we need is a reason to call people!

Welcome to my new web site. I was getting bored with the old one and I didn’t have the time or inclination to maintain it. As a result, the security holes that are often found in php-Nuke were not getting patched and it was only a matter of time before somebody hacked it (again).

This web site is run on WordPress which I hope will be more secure, but more importantly the security updates will install automagically. I’ve not got around to installing the Gallery yet. I may just leave that on the HumbleBee web site which is our family home page.

That’s all for now. I hope that you like the changes.