Uptick in NDRs from major ISPs

While the number of SORBS blacklist entries have declined dramatically since last week, we are noticing an uptick in Non Delivery Reports (NDRs) from ISPs such as Verizon, Yahoo, SBC and Hotmail. In most cases, it appears that these ISPs’ latest netblocks (ranges of IP addresses that include recent spammers) are catching non-spamming companies in their nets, creating bouncebacks to them as well as to the actual spammers.

There have also been a fair number of FIVETEN family blacklist occurrences since Friday — identifying miscellaneous address blocks that have sent spam — which have also included non-spammers in their ranges.

And we are still seeing several reverse DNS issues (PTR records not pointing to the original IP address or missing “A” records), which can make it difficult to get de-listed when requested…and a few viruses identified by CBL. We’ll keep you updated on any changes to these current trends.

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s