My dog hated the mailman *and* the UPS guy. Actually she wasn’t fond of anyone who just walked up to the house with impunity. Once you came inside however, she was your buddy.
There is a bark for that... someone walking up to the house or ringing the doorbell.
I call it, the longbark, as opposed to a playful snappy bark. Its a long, drawn out bark.
A longbark is serious business.