[SURBL-Discuss] Combined SURBL A record format (Was: Re:BillStearns' sa-blacklistavailable as SURBL: ws.surbl.org)

Jeff Chan jeffc at surbl.org
Wed Apr 21 04:36:54 CEST 2004

On Wednesday, April 21, 2004, 3:13:44 AM, Simon Byrnand wrote:
> Does the bitwise approach only allow use of the last octet of the ip
> address ? If so, that would limit you to a maximum of 8 merged "sources"
> of matches that could be distinguised. Probably not a problem in practice,
> but still a theoretical downside.

Other combined lists seem to used only 8 bits, i.e. 8 sources:


> Using the DNSBL

> In opm.blitzed.org, the A record has an IP address of 127.1.0.x
> where x is a bitmask of the types of proxy that have been
> reported to be running on the host. The values of the bitmask
> are as follows: 
> WinGate       1
> SOCKS         2
> Router        8
> HTTP POST     16

In principle bits in the other octets could also be used, but in
practice I don't see us having more than 8 sources.  The question
of how to do a combined list is still open however, so comments
continue to be welcome.

Jeff C.

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