While the majority of requests since Friday have been from a large variety of ISP accounts…the common thread has been the continued elevation of reverse DNS issues. Most common scenarios have shown outbound IP addresses (“A” records) matching up with ISPs’ domains (PTR records) rather than the users…and we’re still noticing missing PTR and “A” records. Remember, any of these situations can make it difficult for receiving DNS servers to trust the senders.
Otherwise, it’s been the usual mix of RBLs listing ranges of IP addresses…or identifying static IP addresses as dynamic…with only a few isolated reports of spam messages being sent directly from the specific IP addresses.
In an unusual development, we’ve now received multiple requests from companies that have received bounceback messages from Yahoo accounts stating that SORBS blacklists were used to reject their emails. This is the first time we’ve heard of a “meeting of the minds” between ISP hosts and RBL companies. Up to now, that relationship has been more one of two opposing army camps…with neither side willing to see the other’s point of view. It will be interesting to see if this apparent change in attitude turns into a trend.