Editing UUCP (section)

===Bang path===
An email address of this form was known as a '''bang path'''.
Bang paths of eight to ten machines (or ''hops'') were not uncommon in 1981, and late-night dial-up UUCP links could cause week-long transmission times. Bang paths were often selected by both transmission time and reliability, as messages would often get lost.  Some hosts went so far as to try to "[[Rewriting|rewrite]]" the path, sending mail via "faster" routes—this practice tended to be frowned upon.

The "pseudo-domain" ending '''[[.uucp]]''' was sometimes used to designate a hostname as being reachable by UUCP networking, although this was never formally registered in the [[domain name system]] (DNS) as a [[top-level domain]].  The uucp community administered itself and did not mesh well with the administration methods and regulations governing the DNS; .uucp works where it needs to{{where|date=January 2017}}; some hosts{{which|date=January 2017}} punt mail out of SMTP queue into uucp queues on gateway machines if a .uucp address is recognized on an incoming SMTP connection.{{citation needed|date=January 2017}}

[[Usenet]] traffic was originally transmitted over the UUCP protocol, typically over dialup modems. At each receiving node, each Usenet article's ''Path'' header line would have the current node's name prepended to the path, separated by "!".  For example, an article that came in from node ''utzoo'' to node ''decvax'' with ''Path: [[Henry Spencer|utzoo!henry]]'' would have that line change to ''Path: decvax!utzoo!henry'').  Usenet software would then send a copy of each article to every neighbor node which had been configured to receive the newsgroup(s) that the article had been posted to -- unless that neighbor was already in the ''Path'' line.  These paths were thus used to ensure that articles did not "loop" back to a node that already had them.

In general, like other [[Non-Internet email address|older e-mail address formats]], bang paths have now been superseded by the "[[Email address#Syntax|@ notation]]", even by sites still using UUCP.  A UUCP-only site can register a DNS domain name, and have the DNS server that handles that domain provide [[MX record]]s that cause Internet mail to that site to be delivered to a UUCP host on the Internet that can then deliver the mail to the UUCP site.