Editing Infinite loop (section)

==Multi-party loops==
An infinite loop may be caused by several entities interacting. Consider a server that always replies with an error message if it does not understand the request. Even if there is no possibility for an infinite loop within the server itself, a system comprising two of them (''A'' and ''B'') may loop endlessly: if ''A'' receives a message of unknown type from ''B'', then ''A'' replies with an error message to ''B''; if ''B'' does not understand the error message, it replies to ''A'' with its own error message; if ''A'' does not understand the error message from ''B'', it sends yet another error message, and so on.

One common example of such situation is an email loop. An example of an email loop is if someone receives mail from a no reply inbox, but their auto-response is on. They will reply to the no reply inbox, triggering the "this is a no reply inbox" response. This will be sent to the user, who then sends an auto reply to the no-reply inbox, and so on and so forth.