On 07/05/26 09:58 AM, Philipp wrote: > Hi > > [2026-07-05 09:18] Martin Kjær Jørgensen <[email protected]> >> In smtpd.conf(5) it says: >> >> smtp limit max-mails count >> Limit the number of messages to count for each session. The default is >> 100. >> smtp limit max-rcpt count >> Limit the number of recipients to count for each transaction. The >> default is 1000. >> >> I am puzzled about what consequences it has to set those variables. For >> instance, I thought 'smtp limit max-mails 10' whould mean smtpd would send >> max >> 10 emails per smtp session with a single server, and queue the rest for >> later. > > I think you misunderstand where these limits are entforced. This are > incomming limits. So when a smtp client (an other mailserver or an user > mail programm) connect to smtpd the limits are enforced. > >> I tried set 'smtp limit max-mails 10' and send an email to more than 10 >> receivers in To: header, but it seems smtpd sends all emials at once to the >> same host anyway. > > Each mail can have multible recipients. When you add addresses to the > To header field your mailprogramm normaly just send one mail with > multible recipients to smtpd. It might change when you use bcc. So your > check result in one mail with more than 10 recipient (but less then > 1000) so smtpd accepted the mail. > > The max-mails limit is when over one connection is more then one mail > send. This happens between mail servers when the sender has different > mails for your domain. Then the sender starts a new mail transaction > after the the first mail send. > >> Could someone clarify for me what consequences it has for mail delivery when >> the limits are reached? > > When the limits are reached smtpd will issue a temporary error > indicating to the sender that he has to slow down. In particular > the error code 452 which is dedicated for this error[0]. > > I hope this awnsers your questions. > > Philipp > > Ps: the commit changing the error code from 451 to 452 is not in the > portable repo. > > [0] https://datatracker.ietf.org/doc/html/rfc5321#section-4.5.3.1.9 >
Thanks, that cleared it up for me. Should we perhaps add your explanations to the smtpd.conf(5) manual? -- /Martin
