However, I soon found that I was having problems sending e-mail via my phone. I checked and re-checked the settings, but couldn’t see anything wrong with them. They work on my laptop, I figured, so there’s no reason that they shouldn’t work on the phone too. However, when I discovered that the same settings also failed on the laptop when it was connected via the mobile phone – yet they worked fine via any number of random wi-fi hotspots – a re-think was required.

It turns out that Vodafone blocks outgoing SMTP connections via port 25 to any servers other than its own, probably as an anti-spam measure. I was trying to use the SMTP server that my domain provider makes available to customers who can’t rely on a particular ISP – ideal for the transient, changeable nature of wi-fi access – when instead I needed to configure my mail client’s outgoing SMTP server to be send.vodafone.net instead. After I changed it, my Outbox emptied.

However, that didn’t seem like the right solution. The next time I used the laptop via wi-fi, outgoing e-mail would fail again because I would no longer be connecting via Vodafone. Back to the drawing board. I did some digging around and discovered that my domain provider’s SMTP server can also be accessed via SSL on port 465. I tested it and was pleased when it worked. That’s a solution that will stand me in good stead regardless of the underlying internet connection.

The moral of this story is that outgoing SMTP server settings that work well in one environment aren’t necessarily appropriate in another. The average home desktop PC user who only ever connects via a single broadband provider will rarely have to think about this kind of thing. However, people who are beginning to take advantage of the increasing number of cheap mobile broadband services now available will need to ensure that their settings work in multiple environments.