Hello, imagine, a mail envolope contains many recipient, The server accepts the first recipients and rejects the last recipients, meaning “Too many recipients in this transaction”.
RFC 821 specifies the reply code 452 as “Insufficient storage”, which RFC 5821 amends, by stating that 452 can mean also too many recipients in this transaction. RFC 3463 defines enhanced status code 4.5.3 stating “Too many recipients”. RFC 5248 attaches the ESC 4.5.3 to reply code 451, stating that changing this binding requires a specification, and there is no such specitifaciton. The latter means, that 452 4.5.3 is not valid. Looking only on the source code Postfix 3.4.6 and sendmail 8.16.0.41 send “452 4.5.3 Error: too many recipients”. Please consider using either “451 4.5.3” or just “452”. I think the former is better, as then the SMTP client cannot conclude that after a while somebody will free space and the SMTP client shall retry after a while. 4.5.3 means that a retry can be done immediately. How can Postfix be tweaked to retry immediately: • Does Postfix interpret 4.5.3 or handle 451 and 452 differently by default? • If a site publishes many MX records pointing to the same IP address, will Postfix do a lot of tries (reducing the amount of pending recipients in each iteration) in shortes time? • If a site published one MX records pointing to many different IPv6 addresses, will Postfix do a lot of tries to deliver the same message in shortest time? I guess, that a site publishing many MX records pointing to many IP addresses is not an additional option to increas the retry rate. Regards Дилян
