Ports and Protocols

Mailborder servers use various ports and protocols for handling web and email traffic. The required ports and protocols are listed below for Mailborder servers to function properly.

Inbound connections to services such as SSH or web can be controlled with a firewall, but outbound connections should not be restricted as doing so will either severely degrade server performance or break it all together. For example, many spam and virus updates are requested via ports 80 and 443 TCP.

Note that an inbound connection to the Master server from each Child server is required on port 443 TCP (https) for logging and task management. 


Used on or Bound to Public Interface

Service  Port  Protocol  Network Flow 
web 80, 443 TCP Both
smtp 25 TCP Both
smtps* 465 TCP In
submission* 587 TCP In
razor 2703 TCP Out
dns 53  UDP  Out 
PGP 11371 TCP


Pyzor 24441 UDP




*Enabling firewall access to 465 and 587 is optional. 


Bound to Loopback Interface

Service Port Protocol Purpose
 mailborder 10025 TCP milter in
 mailborder 10026 TCP milter out
 dkim 1255  TCP  signing 
 dmarc 1256  TCP  authentication
 spamd 783  TCP  spamassassin 
 searchd 9306 TCP sphinx
 mysqld 3306 TCP  database 
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  • 0
    Simon Hedger

    Also outbound UDP 24441 for  PYZOR

  • 0
    Jerry Benton

    Thanks. Added it. 

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