Back in the dark past of the late 1980s/early 1990s, "[x.x.x.x]" used to be a convention to force parsing as an IP address rather than a DNS name. I have no ide

Back in the dark past of the late 1980s/early 1990s, "[x.x.x.x]" used to be a convention to force parsing as an IP address rather than a DNS name. I have no idea where this convention came from, or where it went to, but it seems to have completely vanished since. It's possible that it was a UK-specific convention that was borne from JANET but I don't know; I do know that PAD and CPAD addresses (from X.25) were more common on JANET than IP addresses, so that seems unlikely.