This is an original planning guide. It is not a vendor manual, an official standard, or legal advice. Example addresses use documentation ranges. Review every command before you paste it.
What this hour is for
The converter maps a short list. mailq and exim -bp become postqueue -p. sendmail -q and exim -q become postqueue -f. newaliases stays newaliases. makemap becomes postmap. It does not reload Postfix, Exim, or Sendmail.
One command you already use. Do not turn the host into an open relay. Do not reload during the reading. The mail server is one you administer.
192.0.2.10/24 and example.com are documentation. They stay in the note.
The change you can finish
Apply nothing while you are writing the note. When the lab window opens, it is one change on the host named in the ticket. Read the draft, then the host, then decide.
Rollback is the file, the package version, or the snapshot you saved first. You do not invent a rollback after the only copy is gone.
- Type one command from the short list.
- Read the Postfix twin.
- Leave the relay policy alone.
- Do not reload.
- Stop.
Mistakes that outlive the command
Postfix vs Exim vs Sendmail goes wrong in a small set of ways. The list is here so the ticket can forbid them before the window.
- A reload during the reading.
- An open relay.
- A command outside the list treated as translated.
- A server you do not administer.
Decisions to write down
One decision for Postfix vs Exim vs Sendmail: One command. The twin is from the short list. The relay policy is unchanged. And nothing was reloaded.
Checks before you call it done
Confirm this before you call the change done: The command is written. The twin is written. Nothing was reloaded. The relay policy is unchanged. And the server is yours. If one of those fails, stop.
# mailq maps to postqueue -p.
# A command outside the list is not translated.
# Do not reload during the reading.Before you leave the host
Postfix vs Exim vs Sendmail ends when the hostname in the prompt matches the hostname in the ticket. If it does not, you are on the wrong host. Stop. A command that succeeded on the wrong host is not progress.
The draft stays a draft until a person has read the names in it. A generator does not log into the host and does not know which disk is empty. You delete a line that names a host, a path, or an account you did not write down.
192.0.2.10/24, gateway 192.0.2.1, 198.51.100.0/24, 203.0.113.0/24, and 2001:db8::/32 are documentation. example.com is a documentation name. They belong in the note. They are not values you leave on a host because a draft included them.
prompt-for-this is a reminder that a secret is missing. It is not a password, a key, or a token you save in the ticket or in git. The real secret stays in the password store.
One change is the window. If two things move and the result is wrong, you will not know which one did it. The next change waits for its own page.
If the same step fails twice, stop for the day. The failure is the result. Adding a forum command beside a half-applied change produces a host nobody can rebuild. Restore the copy you took first.
A second person reads the hostname and the change aloud. If they cannot find them in the ticket, the note is not done. Silence is not agreement. Then leave the host alone.
This page is a planning guide. It is not a vendor manual, not an official standard, and not permission to touch a host you do not administer. You do not disable a firewall, AppArmor, or SELinux to make a check pass.
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