http://www.chaosreigns.com/mtx/policy/
Be sure to check out the flow chart at the bottom. It doesn't include delegation. Thanks to Jonas Eckerman for getting me to do it. The SA plugin is still on http://www.chaosreigns.com/mtx/ MTX Policy enables new tests which can be used in place of MTX_FAIL: MTX_NONE MTX_NEUTRAL MTX_SOFTFAIL MTX_HARDFAIL If you don't use them, and use MTX_FAIL instead, it skips the policy check. The values are determined by A records named policy.mtx.example.com. The value of that record also indicates whether the subdomain should be checked. My implementation has an arbitrary limit of 20 levels of domains to avoid abuse. Mail::SpamAssassin::Util::RegistrarBoundaries::trim_domain has been great for picking the domain level to start out at. Thanks again to Jonas for pointing me to it. MTX's debug output showing policy delegation: mtx: Doing the necessary DNS lookups. mtx: Testing IP: 159.134.118.53 (last untrusted relay). mtx: Host name ('A' record) is mail24.svc.cra.dublin.eircom.net. mtx: Relevant MTX record is: 53.118.134.159.mtx.mail24.svc.cra.dublin.eircom.net mtx: Checking blacklist. mtx: Failed to get A record for 53.118.134.159.mtx.mail24.svc.cra.dublin.eircom.net. mtx: Checking MTX Policy. mtx: Policy mindepth: 2, maxdepth: 6 mtx: MTX Policy record name: policy.mtx.eircom.net, depth: 2 mtx: MTX Policy record value: 127.0.1.2. mtx: Delegated. mtx: Found HardFail. mtx: MTX Policy record name: policy.mtx.dublin.eircom.net, depth: 3 mtx: MTX Policy record value: 127.0.1.1. mtx: Delegated. mtx: Found SoftFail. mtx: MTX Policy record name: policy.mtx.cra.dublin.eircom.net, depth: 4 mtx: MTX Policy record value: 127.0.0.0. mtx: Not delegated. mtx: Found Neutral. rules: ran eval rule MTX_FAIL ======> got hit (1) rules: ran eval rule MTX_NEUTRAL ======> got hit (1) My post to the Anti-Spam Research Group's list: http://www.ietf.org/mail-archive/web/asrg/current/msg16232.html -- "To my mind it is wholly irresponsible to go into the world incapable of preventing violence, injury, crime, and death. How feeble is the mindset to accept defenselessness. How unnatural. How cheap. How cowardly. How pathetic." - Ted Nugent http://www.ChaosReigns.com
