> > (1) Use parentheses '(' and ')' to delimit the port number from a
> > host address or name. The has the following advantages over any
> > other proposed solution thus far:
>
> Yes, that's not a bad idea at all. Even [1.2.3.4(2345)] doesn't look too
> bad. The only disadvantage I see is that you'd have to quote them in
> shell commands such as
>
> exim -bh '1.2.3.4(2345)'
>
> but people are used to shell quoting, and you don't run those commands
> all that often.
It causes a problem in Received: headers, though, as ) ends a comment.
I agree that people can use shell quotes and vote for ! as in Plan 9.
Michael