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
IPv4 is the plan you already run. IPv6 is the plan you add when the hosts and the gear can forward it. Dual-stack means both exist on purpose, with a prefix and a gateway for each, not an address family enabled and forgotten.
IPv6 does not remove the need to subnet. It changes the usual LAN length. IPv4 private space does not have an IPv6 twin you may invent. 2001:db8::/32 is documentation.
A translation or a tunnel is a third design. Do not turn it on because a checkbox was near the address family. Name it or leave it off.
This comparison does not migrate a network. It records the choice for one site.
The change you can finish
Apply nothing during the writing of the note. When the lab window opens, it is one change on the device named in the ticket. Read the draft, then the device, then decide.
Rollback is the file or the revision you saved first. You do not invent a rollback after the only copy is gone.
- Name the site.
- Say whether hosts need IPv6 this year.
- Write the IPv4 prefix you already have.
- Write the IPv6 prefix only if you were allocated one.
- Say dual-stack, IPv4 only, or IPv6 only.
- Leave the cutover unscheduled.
Mistakes that outlive the command
IPv4 vs IPv6 goes wrong in a small set of ways. The list is here so the ticket can forbid them before the window.
- IPv6 enabled with no prefix.
- A documentation prefix used as the allocation.
- A tunnel added in the same hour.
- Assuming IPv6 removes firewall rules.
Decisions to write down
One decision for IPv4 vs IPv6: The site is named. The choice is one of three. Each family you keep has a prefix. And translation is off or separately named.
Checks before you call it done
Confirm this before you call the change done: The choice is written. Prefixes match the choice. No documentation prefix was applied. No tunnel was added. And firewall intent is unchanged until its own ticket. If one of those fails, stop.
One site. One choice.
2001:db8::/32 is not your allocation.Before you leave the device
IPv4 vs IPv6 ends when the hostname on the device matches the hostname in the ticket. If it does not, you are on the wrong box. Stop. A command that succeeded on the wrong box is not progress.
The draft stays a draft until a person has read the names in it. A generator does not log into the device and does not know which interface is the uplink. You delete a line that names a device, a zone, or a prefix you did not write down.
0.0.0.0/0 is not kept because a sample included it. A source you can say is the source you keep. 192.0.2.0/24, 198.51.100.0/24, 203.0.113.0/24, and 2001:db8::/32 are documentation. They belong in the note. They are not prefixes you type onto a production device because they appeared in a draft.
prompt-for-this is a reminder that a secret is missing. It is not a password, a key, a community string, or a pre-shared key you save in the ticket or in git. The real secret stays in the store.
One change is the window. A VLAN and a routing protocol and a VPN do not share it. If two things move and the result is wrong, you will not know which one did it. The next feature 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 config produces a device nobody can rebuild. Restore the copy you took first.
A second person reads the device name and the change aloud. If they cannot find them in the ticket, the note is not done. Silence is not agreement. Then leave the device alone.
This page is a planning guide. It is not a vendor manual, not an official standard, and not a permission to touch a network you do not administer. The pillar guide owns the wider design. This page owns one lab proof.
Tools for this guide
This guide does not name a browser tool. The pillar it belongs to links the calculators for the neighbouring work.
Related pillar guides
More in this cluster
The pillar for this page, and the next published pages filed with it.