Spam prevention
Filed under: Business, IT Support, Security —
Posted: 5:51 am
28 April 2008
Recently we had some problems with our DNS provider for the business which caused us to look at moving the domain over to another more reliable provider. In the end we decided to settle with hosting the DNS with pipex and while they may not have always had the best reputation they are one of the larger players, considering the problems recently meant that we had no email or website traffic we were not able to get caught with that again. All went well with the transfer as I made sure that all of the DNS records were live before the actual transfer took place so the transition was completely seamless. However, since then it would seem that the spammer capitalised on one oversight that I made during the transfer; this was SPF (Sender Policy Framework). For those that don’t know what this is basically it is a TXT record within DNS which defines the hostnames and/or IP addresses which can receive and send mail for the domain name it applies to. This TXT record is read by any mail server that can support it and should the email not have originated from the correct address then it is treated as spam and discarded as such. If, however, the mail originates from a valid address then it is processed as normal and passed on to the recipient. On the other hand if the recipient mail server does not support SPF then this information is simply ignored. Since I hadn’t got this information handy I was tasked with re-creating the SPF data which for those that have looked it is not the most straightforward thing to do however Microsoft have very kindly created a wizard on their website which takes out most of the work. The address is as follows: http://www.microsoft.com/mscorp/safety/content/technologies/senderid/wizard/
Using this wizard you are able to enter your domain name and it will process the DNS record to see what settings exist with regard to mail servers and then guide you through the process of creating the SPF data. Over the past few years I have using a number of tools but this has to be the easiest to follow. So check it out, the more people that use SPF the less spam will be possible.
As always thanks for reading and if you have any questions then drop me a line.
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Light relief
Filed under: Personal —
Posted: 9:52 pm
26 April 2008
As anyone in IT will tell you most of your time is spent in front of a computer and if you work in support then a whole heap of that is spent watching progress bars descend into the abyss of life. I would estimate now that I have spent approximately 40% of my working time watching progress bars move across the screen just waiting from something to finish installing or uninstalling. Then as IT people we go home, see our family, then start working again or at least that is how my life tends to pan out. However now that the better weather has finally started I was able to get out in the garden today and start to get things straight so that the kids could enjoy the summer. 
As with many other people we enjoy nothing better than a BBQ in the summer and part of that is to make sure that the garden is fit for the occasion. The kids also really enjoyed being out there today as they were able to get scooters and stuff out and really play and for those who know me Danny was able to really have his first play outside. For those that don’t know me, our youngest was born in July ‘06 and was born with a great deal of problems and we are told he is "one of a kind" as no child with problems as severe as his has ever survived, to see more on Danny go to his blog www.potter-tate.co.uk. Any how Danny had a great time out there as you can see for yourself.
While it was a great day outdoors for a change it would seem that the forecast is back to being shite tomorrow as they are expecting heavy rain again. Still one day out is better than nothing!!
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Linksys woes
Filed under: Business, IT Support, VoIP —
Posted: 6:49 am
21 April 2008
Over the weekend I was onsite finishing off and installation for a client of a VoIP PBX system that we had provided. What they had got was one of IP PBX’s with 4 Linksys SPA941 IP Phones connect to 2 ISDN2e lines so that they had 4 incoming calls. Due to the nature of their business they get a large volume of calls and the 2 analogue lines they had previously was just not cutting it. Anyway, I connected the last phone to the system and decided to set the daylight savings time rule on the SPA handsets so that BST would be correct on the handsets.
So I dutifully changed the config on server so that the new correct dates were inserted and then did a factory reset on the handset to force it to get the correct configuration downloaded to the handset……boy was that a mistake!! What actually happened was that it downloaded the configuration for the server, restarted and when it came up again the display was not working it simply displayed the text logo for the handset. Now to all intents and purposes it looked as though the firmware had fried which was not something that pleases anyone. However, after downloading the firmware from the Linksys website it continued to do the same thing and as the display was screwed I couldn’t use the setup option to perform another factory reset. Anyway, after much backtracking I finally got the old daylight saving time rule from another handset and changed the configuration file on the server along with on the handset and rebooted and finally all was back to normal. At this time I still don’t know why the rule upset the phone so much but what I do know is that it caused be about 2 hours of hassle the I could have done without on a Saturday. Once I have tested this out in the lab I will let you all know the fix.
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