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SYS-C0776 · Web Server Guides

How to Configure SSL/TLS on Caddy

Plan one SSL/TLS change on a lab Caddy host, and read the draft before you paste it.

Updated 25 October 2026 · How-To

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

How to Configure SSL/TLS on Caddy is one lab change on a Caddy host you administer. TLS here is one certificate for one name you control, and a protocol list you can say. The browser tool drafts text. It does not log in.

Caddy. Automatic HTTPS applies only to a name you control. example.com is not that name. The check is a Caddy validate, or the equivalent check this install documents, before a reload. The file is a Caddyfile site block.

One name. The private key stays on that host. Do not enable an old protocol to satisfy an unnamed client. Do not put the private key in the ticket. The name matches the certificate, and the config test passes.

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.

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.

  1. Write the hostname and confirm you administer it.
  2. Save the current file, package list, or snapshot before any draft is applied.
  3. Generate the draft and delete every line this ticket did not name.
  4. Remove documentation addresses, example.com, and any secret.
  5. Apply one change only when the lab window is open and a console or a second session exists.
  6. Read the result back and compare it with the ticket.
  7. Stop. The next change is a different page.

Mistakes that outlive the command

SSL/TLS on Caddy goes wrong in a small set of ways. The list is here so the ticket can forbid them before the window.

Decisions to write down

One decision for SSL/TLS on Caddy: The hostname matches the ticket. The change is only SSL/TLS. The platform is Caddy. A current copy was saved first. No secret is in the note. And the proof you expect is: The name matches the certificate, and the config test passes.

Checks before you call it done

Confirm this before you call the change done: The hostname was read from the host. The saved rollback exists. The draft was edited. One change was applied, or none yet because this was the writing hour. The read-back matches the ticket. And management still works. If one of those fails, stop.

# Caddy lab. Review before you paste.
# Change: SSL/TLS.
# a Caddy validate, or the equivalent check this install documents, before a reload
# prompt-for-this is not a password.
# Delete 0.0.0.0/0 if a sample included it.
# 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.

Before you leave the host

How to Configure SSL/TLS on Caddy 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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