[JAMES-3820] DNS Blocklist: implement DNSRBLHandler as MailHook instead of RcptHook

• Type: Improvement
• Status: Closed
• Priority: Minor
• Resolution: Fixed
• Component/s: SMTPServer
• Assignee: Unassigned
• Reporter: ouvtam
• Created: 25/Sep/22 13:42
• Updated: 20/Oct/22 02:01
• Resolved: 20/Oct/22 02:01

Description

At the moment the DNSRBL handler (org.apache.james.protocols.smtp.core.fastfail.DNSRBLHandler) is implemented as a RcptHook. Thus, for every RCPT TO call this handler will be called and a blocklist lookup will be issued.

One can argue It makes sense to implement the handler as a ConnectHandler, so the blocklist check is done as early as possible. However, if SMTP AUTH is successful then we should allow the connecting client anyway.

Therefore it makes sense to implement the DNSRBL handler at MAIL FROM stage that is MailHook. One exception is the following. According to RFC 4954, authentication information can optionally provided as ESMTP AUTH parameter with a single value in the 'MAIL FROM:' command.

 

 

 

Issue Links

• relates to: JAMES-3819 [GSOC] James as a (distributed) MX server
• links to: GitHub Pull Request #1207