[SURBL-Discuss] SURBL querying engine?

Jeff Chan jeffc at surbl.org
Sun Jul 18 17:09:44 CEST 2004

On Sunday, July 18, 2004, 3:03:38 PM, Patrik Nilsson wrote:
> At 13:34 2004-07-18 -0700, Jeff Chan wrote:

>>Wouldn't dns_get_record() in PHP, specifically the DNS_A option
>>resolve domains?

> dns_get_record is PHP 5 only*, which was in beta until last week.
> Many installations will probably stay with 4.x until 5.1 is released.

> If you only want to check the existence of an A record, with 4.x, you can 
> use checkdnsrr instead.
> http://us2.php.net/manual/en/function.checkdnsrr.php

> You can not get TXT records with checkdnsrr though, so if you want check 
> those as well under PHP 4.x (multi.surbl.org is more interesting if you 
> do...), you have to use work-arounds, like directly calling exec nslookup.

Thanks for the addition info about name resolution under php Patrik.

For everyone's info, we recommend using the A records for any
sort of automated procedures rather than the TXT records.  The
A records are likely to be the most stable.

For multi.surbl.org, the A records are encoded in a simple
bitmasking scheme where each source list has a corresponding
bit position.  More details are at:


Jeff C.

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