Bounce Codes for Major ISPs
There are so many bounce codes used by the various ISPs and receivers that it’s hard to keep them all straight.
Now there is a great resource for most of the known bounce codes to help simplify your tracking and processing. The eec’s Deliverability Roundtable has put together a repository of common and available bounce strings senders might see from current ISPs (email receivers).
The forum is set up on Get Satisfaction as a dynamic and interactive site that allows users to request information and update bounce strings as they change. The ISP serving the bounce, the bounce string text and next steps for a sender are written out by bounce code here.