1 qmail-smtpd Receive message by SMTP from another host:
3 | MAIL FROM:<joe@heaven.af.mil>
4 | RCPT TO:<bill@irs.gov>
6 | Is $RELAYCLIENT set? Yes: "".
10 qmail-queue Store message safely on disk.
15 qmail-send Look at envelope recipient, bill@irs.gov.
16 | Is irs.gov in locals? No.
17 | Is bill@irs.gov in virtualdomains? No.
18 | Is irs.gov in virtualdomains? No.
19 | Is .gov in virtualdomains? No.
20 | Deliver remotely to bill@irs.gov.
23 qmail-rspawn Run qmail-remote.
28 qmail-remote Look at host name, irs.gov.
29 Is irs.gov listed in smtproutes? No.
30 Look up DNS MX/A for irs.gov and connect to it by SMTP:
32 MAIL FROM:<joe@heaven.af.mil>
33 RCPT TO:<bill@irs.gov>