MessageLabs (Symantec Hosted Services), a well known internet security firm, has taken flak after customers of the BT Business broadband ISP service found that they were unable to send emails between Monday and Tuesday because a crucial server IP address had been blacklisted due to SPAM (junk email). A post on BT's Customer Forum by one of the operators moderators has since revealed more information.



Sadly the blocking of any ISPs business email addresses, even if just for a day or two, can cause significant financial detriment to customers. It is not known how many people were affected, although some reports claim that up to 200,000 could of been hit (both BT and non-BT internet users).

However MessageLabs has denied any involvement with the blocking, although it's claimed that they make use of a separate blocklist service from UCEProtect which, acting on its own, chose to place a restriction upon the BT IP address.

For its part UCEProtect claims that, "all we want [BT to do] is block port 25 on their dynamic assigned IP's as recommended by the Messaging Anti-Abuse Working Group MAAWG since 2005". This is something that BT and some other UK ISPs have yet to do, although it is quite common in other countries.

Last year UCEProtect claimed that "massive" amounts of SPAM originated from BT's network, which isn't a surprise considering that they have millions of customers. It only takes a handful of customers with bad intentions to send a colossal amount of junk email.