ORBS

Open Relay database check

SurgeMails integrated and flexible open relay database checking (g_orbs_list) can be used enforce a servers blacklisting or whitelisting in one or more ORBS databases. In addition this can be used to mark messages with a header which can then be taken into account in the SmiteCRC"SpamDetect rating" calculation. An ORBS database is simply a DNS server that returns a positive response if a server is listed in the database. A variety of services are available online that can maintain blacklist databases. Normally you would maintain your own whitelist database that overrides the blacklist listings.

eg 1 - A simple deny mail from blacklisted servers could be achieved with:

g_orbs_list name="relays.ordb.org" action="deny"

eg 2 - A smarter setup with exceptions for certain IP ranges and a whilelist exception database, a blacklisted deny database and with useful header based tagging could be achieved as follows:

g_orbs_exception "127.0.0.*,12.34.56.*"
g_orbs_list name="mywhitedatabase.none" action="accept"
g_orbs_list name="relays.ordb.org" action="deny"
g_orbs_list name="bl.spamcop.net" action="stamp" stamp="spamcop, http://spamcop.net/w3m?action=checkblock&ip=||remoteip||"

eg 3 - To use the output of header based ORBS stamping in the Aspam SpamDetect calculation the following could be used:

g_orbs_list name="relays.ordb.org" action="stamp" stamp="open relay"
g_orbs_list name="my.dialup.databse.none" action="stamp" stamp="dialup"

These entries have the following rules in filter.rul. If you used your own stamp text you would place appropriate entries in the local.rul file.

if(rexp_case("X-ORBS-Stamp", "open relay")) then
call spamdetect(4.0, "Sender's IP was on an open relay RBL")
end if

if(rexp_case("X-ORBS-Stamp", "dialup")) then
call spamdetect(4.0, "Sender's IP was on a dialup RBL")
end if

SPF

SPF is a recent mechanism that provides for verification that the sender is actually allowed to send from the domain that they say they are sending from. This has the potental to reduce a very large amount of worldwide spam. For more information see http://netwinsite.com/spf.htm .