MTA
termops culture
Stands for: Mail Transfer Agent
The server that accepts mail and passes it on toward its destination.
It is one of the last places where a machine accepts unsolicited connections from strangers and then acts on their content, which is why mail infrastructure carries so much of the internet's security history: relay controls, reputation lists, authentication records and content filtering were all invented here first. The operational rule that has not changed is that an agent which accepts and forwards without checking who asked will be found and used within hours.
Also known as: Mail Transfer Agent, mail server