juan smitt: > Hi, > > > The clients are very sensitive to the mail service's response time (we > can't do anything with that).
The response time from what? Here is an example conversation: Client connects to server (If DNS is broken, there may be some delay) TCP handshake (If the network is overload there may be some delay) (There may be some delay as the server looks up the client name) Server sends the 220 greeting Client sends EHLO Server replies Client sends MAIL FROM Server replies Client sends RCPT TO Server replies Client sends DATA Server replies Client sends message header, body, and the final "." (There may be some delay due to before-queue header/body checks, Milters, other content filters) Server replies 250 Ok (queued as abcdef) (At this point the client knows that the message is stored) Client sends QUIT Server replies and disconnects. Wietse