imageFor the last month, I noticed occasional problems with sending e-mails from my professional POP-based account (I also have a professional Exchange account but I don’t use this one very much for a lot of historic reasons, like me having a BlackBerry subscription which only worked with POP-based accounts, until I got my new phone). The hosting company that was hosting this POP account was having a lot of problems for months and I was using their SMTP server (requiring SMTPAuth) to send my e-mails from this account. I was busy at that time and just wanted my urgent e-mails to get out so thinking they had yet another breakdown, I switched to my Internet Service Provider (ISP)’s SMTP server (on port 25) and it worked fine. However, that obviously meant that as soon as I would plug my computer to a network using another ISP, this SMTP server would block my e-mails because they are sent from an Internet line leased by a competitor. Of course, changing the SMTP server every time was an unacceptable time loss and bother to do every time, so I set out and investigated.