ARCHIVED: What does the "too many hops" error mean when an email message I send fails?

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When you send an email message over a network, it is transferred to and through several computers before it gets to its destination. Each transfer between computers is called a hop. The "too many hops" error message means there are too many transfers between you and your recipient. To prevent mail forwarding loops, most mail delivery systems limit the number of hops they will process before stopping a delivery attempt.

There is little you can do to correct a "too many hops" mail return. If you think a mail forwarding loop is causing the error, you can contact the person with the loop through a method other than the email address causing the error. If you know a mail forwarding loop is not causing the error, ask your system administrator to increase the maximum number of hops allowed.

Mail forwarding loops

A mail forwarding loop can occur when you set up mail forwarding on two accounts so that the first account forwards all its mail to the second, and the second account forwards mail back to the first. If your mail delivery system had no limit on hops, your message could be bounced back and forth between these two accounts indefinitely.

Frequently, when a message you sent returns to you with the "too many hops" error message, it means the recipient has set up a mail forwarding loop.

Distribution lists

If you are an owner of a distribution list and your list gets the "too many hops" error message, you may have more difficulty identifying the sender because the error message typically does not include the exact email address(es) causing the problem.

Here is an example of the delivery error message:

  | ---------- Forwarded message ----------
  | Date: 11 Jul 2003 15:28:10 -0500
  | From: Mail Delivery Subsystem <>
  | To:
  | Subject: Returned mail: Unable to deliver mail
  |    ----- Transcript of session follows -----
  | 554 sendall: too many hops 26 (25 max): from <>, to | 
  |    ----- Unsent message follows -----
  | Received: from PO3.Indiana.Edu by
  | 	(5.65c+/10jsm) id AA13309; 11 Jul 2003 15:28:10 -0500
  | Received: from by PO2.Indiana.EDU; id AB12765
  | 	(5.67bjsm/2.5.1jsm); 11 Jul 2003 15:28:59 -0500
  | Received: from by PO2.Indiana.EDU; id AA23798
  | 	(5.67bjsm/2.5.1jsm); 11 Jul 2003 15:25:28 -0500
  | Received: by
  | 	( id AA284314343; 11 Jul 2003 15:25:43 -0500

This will be followed by the original message.

Because this error does not indicate the problem address(es), you may need to send the message to smaller groups of individuals on your list to determine where the problem originates from.

This is document beha in the Knowledge Base.
Last modified on 2018-01-18 09:57:41.

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