List mailservers from spf by iterating over spf entries & includes.
Extended to allow for whitelisting and blacklisting of mailservers in postfix to speed up postscreen greylisting.
- list mailservers from spf records
- output blacklist entries for servers
- output whitelist entries for servers
Add domain to whitelist
./spf_permit.sh google.com >> /etc/postfix/postscreen_access.cidr
The Postfix postscreen daemon provides additional protection against mail server overload.
One postscreen process handles multiple inbound SMTP connections,
and decides which clients may talk to a Postfix SMTP server process.
By keeping spambots away, postscreen leaves more SMTP server processes available for legitimate clients,
and delays the onset of server overload conditions.
using the default config
/etc/postfix/main.cf
postscreen_access_list = permit_mynetworks,
cidr:/etc/postfix/postscreen_access.cidr
add entries to /etc/postfix/postscreen_access.cidr
# postscreen access list
# A simple combined white/blacklist
# Only "permit" and "reject" work on the RHS
# This is a CIDR table, so see cidr_table(5) for LHS syntax
you can create seperate files for blacklist / whitelist if desired eg:
/etc/postfix/main.cf
postscreen_access_list = permit_mynetworks,
cidr:/etc/postfix/postscreen_access.cidr,
cidr:/etc/postfix/postscreen_reject.cidr,
cidr:/etc/postfix/postscreen_permit.cidr
Classless Inter-Domain Routing (CIDR) is an expansion of the IP addressing system
that allows for a more efficient and appropriate allocation of addresses.
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