Problems at Cox: Resolved
People mailing to Cox in the wee hours of this morning may have received a rejection message citing the Invaluement DNSBL.
554 IMP a.b.c.d blocked. IPBL100 – Refer to Error Codes section at http://postmaster.cox.net for more information.
I spoke with one of the folks at Cox and they said there was an error in the implementation causing non-listed IPs to be rejected erroneously between about 4am to 8am (Eastern) this morning. The problem has been resolved as of 8am, and all traffic is flowing normally. The also stated that attempts to resend any blocked messages will succeed. They do apologize for any problems this may have caused.
For those of you with aggressive bounce handling, removing addresses after a single 550 bounce, you will also want to re-enable any cox.net subscribers that bounced off during this configuration problem.