Remember "bang paths"? ( host1 ! host2 ! username )
Raise your hands, all of you who had an email address *without* an "@" sign.
I did. But I was young them, and now I'm 50.
🙋
I had a BITNET email address, with a % instead of an @
@purrperl @jmeowmeow @Daojoan I never got to connect to BITNET, but addresses with "%" were not rare during the transition from bang paths to domain addressing.
According to the Linux Network Administrators Guide (vintage 1991 or so): "... user %domainB@domainA is first sent to domainA, which expands the rightmost (in this case, the only) percent sign to an @ sign. The address is now user@domainB, and the mailer happily forwards your message to domainB, which delivers it to user"