State owned telco and ISP MTNL is blocking a part of its broadband network that allows sending of emails through private email servers after ISPs in Mumbai came under a heavy DDoS attack last week, crippling internet speeds in the city. MTNL will be blocking ‘Port 25’ used for sending emails on private servers, which will essentially stop spammers and hackers from sending out bulk emails in a network using hijacked PCs. MTNL has circulated emails to its broadband users; one of our readers had pointed it out to us in a tweet: https://twitter.com/adityawasudeo/status/758861393613291522 For example, I could send and receive mails from my MediaNama mailbox using a standalone Thunderbird email client, and if the mails are routed through Port 25, they will not be sent to the recipient, because of the ISP block on Port 25. Note that I will still be able to receive emails in my private email server, since a different port is used for that. MTNL mentions that some of its users may not have installed an anti virus/spam filtering software, allowing hackers to take control of the PC and carry out DDoS or spam attacks that can clog the entire broadband network. Corporate users have private email servers registered under their domain name, and some of them may not be send and receive emails. MTNL is asking such users to instead use their own private EMTP email servers, by manually configuring email clients like Thunderbird to route email through “smtp.mtnl.net.in”. However, a user on Broadbandforum points out that…
