Postfix

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Revision as of 16:59, 14 February 2022 by Tony (talk | contribs)

Docs

Postfix and smtp auth/sasl


Postfix and Network Solutions certificates

#The private key you created together with privkey.csr, readable for root only!
smtpd_tls_key_file = privkey.pem

#the certificate you received from NS
smtpd_tls_cert_file = /etc/ssl/MY.HOST.COM.crt

#NetworkSolutions_CA.crt and UTNAddTrustServer_CA.crt combined in a single file
smtpd_tls_CAfile = /etc/postfix/intermediate.pem

Postfix and LDAP

Spam filtering

ldap and aliases



man ldap_table
man maildirquota

Tools

  • postfwd

pflogsumm

Log analyzer

vimbadmin

vimbadmin


Notes

  • postconf
  • postsuper

anti spam measures that work for me

smtpd_recipient_restrictions =
   permit_sasl_authenticated,
   reject_unverified_recipient,
   permit_mynetworks,
   reject_sender_login_mismatch,
   reject_invalid_hostname,
   reject_unknown_reverse_client_hostname,
   reject_non_fqdn_hostname,
   reject_non_fqdn_sender,
   reject_non_fqdn_recipient,
   reject_unknown_sender_domain,
   reject_unknown_recipient_domain,
   reject_unauth_destination,
   check_recipient_access  hash:/etc/postfix/recipient_access,
   reject_rbl_client bl.spamcop.net,
  1. reject_rbl_client safe.dnsbl.sorbs.net,
   reject_rbl_client b.barracudacentral.org,
   permit

tls on outgoing mail

smtp_use_tls = yes smtp_tls_security_level = may smtp_tls_CAfile = /etc/pki/tls/certs/ca-bundle.crt smtp_tls_cert_file = /etc/postfix/ssl/domainname.com.pem smtp_tls_key_file = /etc/postfix/ssl/domainname.com.key smtp_tls_session_cache_database = btree:/var/lib/postfix/smtpd_scache smtp_tls_loglevel = 1

CentOS packages

gf-plus repository or epel :)



FAQ

Limit CC

/etc/postfix/header_checks 

/^To:([^@]*@){50,}/ REJECT Sorry, your message has too many recepients.
/^Cc:([^@]*@){50,}/ REJECT Sorry, your message has too many recepients.

 

log subject

Create file /etc/postfix/header_checks and put in: 

/^[Ss]ubject:/  WARN

and in /etc/postfix/main.cf 

header_checks = regexp:/etc/postfix/header_checks

 

rate limit outgoing mail

Probably start with 

smtp_destination_rate_delay = 5s

queue

Clean the postfix queue

mailq | grep ^[A-F0-9]| awk '{ print $1 }'| sed 's/*//' | while read i;do postsuper -d  ${i};done

Or simple: 

postsuper -d ALL

View message in queue

postcat

Delete message from queue

postsuper -d

Requeue mails

postsuper -r ALL

or 

postqueue -f

Postfix as secondary MX

relay_domains = foo.com, bar.com
relay_recipient_maps =
          hash:/etc/postfix/relay_recipients

 

milter-reject 4.7.0 DNS timeout

Most likely caused by sid-filter, aka milter-sid, aka sid-milter. Try adding "-D" to the rc.conf or defaults or whatever file starting it.

postqueue: fatal: Connect to the Postfix showq service: Permission denied

postfix set-permissions

too many concurrent connections

If that's what you get sending to a server you don't control, check 

initial_destination_limit

 

warning: SASL authentication failure: No worthy mechs found

could be missing cyrus-sasl-plain

 

Sender address rejected: need fully-qualified address

myorigin = /etc/mailname


newaliases: fatal: bad string length 0 < 1: setgid_group =

Probably Ubuntu (Debian?), comment out the setgid_group line

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