Our Dallas infrastructure has been under SMTP attack this week. Spammers are using botnets to try authenticate and send junk email. To mitigate the attack, we have implemented geographic access restrictions.
The flood of spam connections were filling up all the connection slots, and some of our users occasionally saw a “too many SMTP connections” error. The culprits were bots (virus-infected computers) in countries that are quite unlikely to have Anno users, e.g. Vietnam, Russia and China. We are now mitigating this attack (temporarily, but maybe long-term) be denying SMTP connections on port 25 to our servers from a lost of “bad” countries.
Clients travelling to foreign countries will not be affected by this if they use alternate SMTP port 587, which is likely already the case. But if you think you are affected by this block, please make contact with us.