qmail-smtpd Receive message by SMTP from another host:
| MAIL FROM:<joe@heaven.af.mil>
| RCPT TO:<bill@irs.gov>
|
| Is $RELAYCLIENT set? Yes: "".
| Accept RCPT.
V
qmail-queue Store message safely on disk.
Trigger qmail-send.
|
V
qmail-send Look at envelope recipient, bill@irs.gov. | Is irs.gov in locals? No. | Is bill@irs.gov in virtualdomains? No. | Is irs.gov in virtualdomains? No. | Is .gov in virtualdomains? No. | Deliver remotely to bill@irs.gov. V
qmail-rspawn Run qmail-remote.
|
V
qmail-remote Look at host name, irs.gov. Is irs.gov listed in smtproutes? No. Look up DNS MX/A for irs.gov and connect to it by SMTP:
MAIL FROM:<joe@heaven.af.mil>
RCPT TO:<bill@irs.gov>