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Spamhaus DBL errors

Sometime in the last few days, Spamhaus seems to have started issuing a block message if someone queries the DBL with an IP address. folks started seeing an uptick in error messages that mention Spamhaus saying:

554 5.7.1 Service unavailable; Client host [x.x.x.x] blocked using dbl.spamhaus.org; No IP queries, see https://www.spamhaus.org/faq/section/Spamhaus%20DBL#279 (in reply to RCPT TO command))

554 5.7.1 Service unavailable; Client host [x.x.x.x] blocked using dbl.spamhaus.org; No IP queries, see https://www.spamhaus.org/faq/section/Spamhaus%20DBL#279 (in reply to RCPT TO command))

Crowdsourcing information from the emailgeeks slack channel makes it look like sometime in the last 2 or 3 days Spamhaus started replying positively to any query of the DBL that was an IP address changed their DBL configuration are querying the list incorrectly. Spamhaus has always returned this code to senders querying the DBL with an IP address.

Basically, anyone who is getting this error message can do nothing about it. This is a configuration error on the receiver’s side. If it continues for much longer, I’d mark the domains as inactive and do not mail. Clearly no one at the domain is home and haven’t noticed they’ve not received any email in days.

Many thanks to Spamhaus for contacting me and setting me straight that this was nothing new and the DBL has always returned 127.0.1.255 to an IP query directed at the DBL.

3 comments

  1. Todd Herr says

    This doesn’t seem like something Spamhaus would do without announcing it first. Back in September, they made a pretty significant change that affected queries from public DNS servers, and let everyone know about it:

    https://www.spamhaus.org/news/article/788/spamhaus-dnsbl-return-codes-technical-update

    I’m not on emailgeeks anymore, though, so I can’t speak further on the topic that this.

  2. rmcguire says

    The DBL is for domains, no? Shouldn’t respond to an IP query

  3. Alex Lasoriti says

    127.0.1.255 has been returned to IP queries to DBL since the DBL start on March 1st, 2010. The FAQ entry https://www.spamhaus.org/faq/section/Spamhaus+DBL#279 goes back to the date.

    That is simply a configuration mistake on the receiver side that needs to be corrected. The receiver is probably rejecting all their mail due to this, so they should be strongly incentivated to fix it quickly.
    This was a decision made at that time to prevent trillions of useless DNS packets from travelling across the wires.

    Alex – Spamhaus Technology

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