Tagopen relay

Relaying Denied

I’ve got multiple clients right now looking for insights about bounce handling. This means I’m doing a lot of thought work about bounces and what they mean and how they match up and how different ISPs manage delivery and how different ESPs manage delivery and how it all fits together. One thing I’ve been trying to do is contextualize bounces based on what the reason is. Despite...

Fun with new mailservers

I’m building a new set of mailservers for wordtothewise.com – our existing mailserver was “I’ll repurpose this test box for a week” about four years ago, so it’s long past time. I tested our new smarthost by sending a test mail to gmail. This is the very first email this IP address has sent in at least three or four years, possibly forever: host gmail-smtp-in.l...

Open relays

Spamhaus wrote about the return of open relays yesterday. What they’re seeing today matches what I see: there is fairly consistent abuse of open relays to send spam. As spam problems go it’s not as serious as compromised machines or abuse-tolerant ESPs / ISPs/ freemail providers – either in terms of volume or user inbox experience – but it’s definitely part of the...

Maybe the sky is only falling a little bit

There was quite a bit of breathless reporting last week about the DoS against Spamhaus and how it was large enough to break the Internet. As the postmortem has gone on, a few things are becoming clear. There was a lot of traffic, enough to swamp some major transit points. Most people, particularly in the US, saw no problems. Network engineers had more than a few sleepless nights trying to route...

Open Relays and Mail Sinks

Email is a “store and forward” protocol. The sender doesn’t connect directly to the recipient to send the mail with just one network hop, rather the sender connects to a mailserver (usually referred to as an “MTA”, short for Mail Transfer Agent) and sends the message there. Once that MTA has received the message it sends it on to another MTA, and so on until it...

Recent Posts

Archives

Follow Us