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 IPsec VPN on Cisco IOS/IOS-XE is one lab change on a Cisco IOS/IOS-XE device you administer. IPsec here is one proposal and one peer. IKEv2 is the version you prefer when both sides can do it. Write the version you actually configured. The browser tool drafts text. It does not log in. You still choose the device.
Cisco IOS uses configure terminal, a show of the running config, and copy running-config startup-config when you mean to keep it. Interface names look like GigabitEthernet. A second SSH session stays open across the change. Matching encryption, matching identities, and a secret that stays in the store.
A proposal of every cipher the menu offers is not a design. A key in the generator output is a key you remove before you save the note. Phase 1 and the child association are up, or you stop and compare the proposal instead of adding a second tunnel. The previous startup config, or a copy you saved off the box, is the rollback.
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. example.com is not your hostname. A second session stays open if the change can lock you out.
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.
- Write the hostname and confirm you administer it.
- Save the current config before any draft is applied.
- Generate the draft and delete every line this ticket did not name.
- Remove any 0.0.0.0/0 and any secret.
- Apply one change only when the lab window is open.
- Read the result back and compare it with the ticket.
- Stop. The next feature is a different page.
Mistakes that outlive the command
IPsec VPN on Cisco IOS/IOS-XE goes wrong in a small set of ways. The list is here so the ticket can forbid them before the window.
- Pasting a draft you did not read.
- The wrong hostname.
- A default password left in place.
- 0.0.0.0/0 kept from a sample.
- A secret in the ticket or in git.
- Two features in one window.
- No saved config before the change.
- A documentation prefix applied on a production device.
- A proposal of every cipher the menu offers is not a design. A key in the generator output is a key you remove before you save the note.
- Calling the generator output a finished production config.
Decisions to write down
One decision for IPsec VPN on Cisco IOS/IOS-XE: The hostname matches the ticket. The feature is only IPsec VPN. The vendor habit was followed: Cisco IOS/IOS-XE. A current config was saved first. No 0.0.0.0/0 remains. No secret is in the note. The proof you expect is: Phase 1 and the child association are up, or you stop and compare the proposal instead of adding a second tunnel. And the parent pillar still owns the design.
Checks before you call it done
Confirm this before you call the change done: The hostname was read from the device. 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. A second person can say what changed. Management still works. And the next feature is not started. If one of those fails, stop.
# Cisco IOS/IOS-XE lab. Review before you paste.
# Feature: IPsec VPN.
# Cisco IOS uses configure terminal, a show of the running config, and copy running-config startup-config when you mean to keep it.
# Delete 0.0.0.0/0.
# prompt-for-this is not a password.
# 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.Before you leave the device
How to Configure IPsec VPN on Cisco IOS/IOS-XE 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.
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