How to write an SPF record

An SPF record is a DNS TXT record (like A records and MX records) that indicates to receiving mail servers whether an email has come from a server that is “allowed” to send email from that domain. I.e. it’s a check that should prevent spammers impersonating your domain. It does rely on the receiving server actually doing the check, which not all do, so it’s not by any means fool proof, but it should help prevent mass email from your organisation to customers being flagged as potential spam.

 

Below is an example SPF record for capitalfmarena.com:

(this is in the public domain – you can look up an organisation’s SPF record by using online SPF checkers)

 

“v=spf1 ip4:93.174.143.18 mx a:service69.mimecast.com mx a:service70.mimecast.com a:capitalfmarena.com -all”

 

V=spf1 specifies the type of record this is. (SPF)

 

Ip4: pass if the IP senders IP address matches the addresses we send mail from.

 

mx a: pass if sender’s IP matches an ‘MX’ record in the domain

 

a: pass if Sender’s IP matches an ‘A’ record in the domain

 

The –all indicates that all other senders fail the spf test. (+all would mean anyone can send mail.)

(~all was used when spf was still being implemented, and is a soft fail, but shouldn’t really be used any longer other than when you’re transitioning between mail hosts or something)

 

Mechanisms are tested in order and any match will pass the email. A non-match results in a neutral state, until it gets to the end of the string where the –all mechanism will fail it.

 

IT & Web Infrastructure Masterclasses

Through March 2013, I’m running a set of IT and Web infrastructure masterclasses in Nottingham (in conjunction with PCM Projects), for people who don’t necessarily work in IT, but need to know (or would benefit from knowing) some of the basics.

The intended audience is small business owners or managers, where you may have to deal with IT contractors or staff and decide IT and web strategy, but you’re not comfortable that you know enough about it to make informed decisions. For example, there are an almost infinite number of ways to keep your business data accessible, secure, backed up, and away from prying eyes, but which way is best for you? How should you manage your website – should you pay someone else to design and host it, or bring it in-house? How should you handle email, on what sort of server? How should you plan for business growth? How do you protect your business from viruses, malware, spam, and hacking attempts?

These are the sort of questions that I will help you with – you don’t need any knowledge of IT or the web already, and because the groups are small – around 6 people – you’ll be able to ask questions and find out information specific to how your business operates.

You’ll then have enough knowledge to go to your suppliers or contractors, and ask the right questions, purchase the right services, at the right price.

There are four sessions, as below, and you can book yourself on them by visiting the eventbrite page for the events. Contact me for any further information.

 

Technically Speaking – 4 March

Topics to include: an overview of web/IT infrastructure and how it all fits together; an update on the current climate; domain names, analytics, and connections to social technology.

 

Email & Communication – 11 March

Topics to include: different service providers and set-ups (e.g., using hosted email, managing it in-house) and getting it all working for PCs and on mobile devices; good email practice, transferring data and keeping it secure.

 

Internet Security – 18 March

Topics to include: how to stay safe and keep trading; what are the threats – viruses, hack attacks, theft, loss of confidential or valuable data; keeping your business (and family) safe on the internet; and keeping your systems up to date and secure.

 

Data storage – 25 March

Topics to include: managing data storage and growth in your business; internal networks and cloud storage; back-ups; access controls, speed vs. reliability vs. cost.

Snowdon in the snow

I recently took a week off work to go biking, snowboarding, climbing, and hiking and stuff. Part of the trip included a visit to Wales to stay at penmachno after riding llandegla. I was going to ride penmachno the following day, but the weather was dreadful, so I walked halfway up snowdon instead 🙂

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Mountain biking in the snow – sherwood pines, Nottingham.

Sherwood pines is a nice little place to ride – the main trail is quite short, but is pretty much 100% twisty fast singletrack, and you can get a couple of loops done in two hours. I went for a ride there recently in the heavy snow, and I was so lucky to have the trail to myself. The snow was fresh – no foot prints or tyre tracks, and it was deathly silent in the woods with the snow falling heavily. Absolutely brilliant, although I couldn’t feel my feet after 15 minutes or so…

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