Does T-Mobile block unauthenticated SMTP to prevent spam email?
Background We’ve identified that unsolicited spam email is originating from our mobile network. This generally takes the form of unauthenticated Simple Mail Transfer Protocol (SMTP). There are a few possible reasons for this: • A customer’s computer has been infected with a virus or ‘bot’ which sends lots of spam email over our network when a customer uses their mobile device to connect to the internet. Normally the customer will not be aware that this is happening. • Real ‘spammers’ are using mobile devices connected to our network to send huge volumes of unsolicited spam email Some of T-Mobile’s IP addresses have been blacklisted by various spam prevention organisations. The result is that, on occasion, genuine customers are unable to have their emails delivered to the recipient. In order to safeguard the majority of our customers’ email services, and reduce spamming generally, T-Mobile are making a small but significant change to our network to help prevent the propagation of spam e
