Multiple IPs on single interface (Network Configuration) by trinkel · Pull Request #465 · canonical/ubuntu-server-documentation

trinkel · 2026-01-12T00:42:35Z

Description

Adds instructions for creating multiple IPs on a single interface to the network configuration documentation.

Related Issue

Partially fixes #212

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[docs] Add instructions to configure virtual IPs to the Network Configuration page

Checklist

I have read and followed the Ubuntu Server contributing guide.
My pull request is linked to an existing issue (if applicable).
I have tested my changes, and they work as expected.

Additional Notes (Optional)

This PR addresses some of the discussion in #212. I will be continuing with additional updates to the Network Configuration page and was advised not to create a new issue for the continuation.

Thank you for contributing to the Ubuntu Server documentation!

**configuring-networks.md** - Add section explaining how to add additional IPs to a typical network configuration.

**configuring-networks.md** - Add `netplan` version with DHCP - Add note about DHCP limitation

**configuring-networks.md** - Minor grammar changes to three paragraphs.

**configuring-networks.md** - Move _Adding a virtual IP address_ section - Was a level 2 heading under _Configuring networks_ - Now a level 3 heading under _IP Addressing_

**configuring-networks.md** - Remove early apply and verify instructions from _Adding a virtual IP address_ section - Create a single _Apply and verify..._ section a conclusion to the _Adding a virtual IP address_ section

**configuring-networks.md** - change look of code comments in _Adding a virtual IP_ section

**configuring-networks.md** - Add that virtual IP is used on single network interface - Fix wording of website virtual host usage

…ntu-server-documentation into add-virtual-ip-configuration

trinkel · 2026-01-12T00:50:32Z

There is a statement in my updated text that only one IP on an interface can be furnished by DHCP. I consulted several sources and this is true to the best of my knowledge. Also, it doesn't appear that there is a way to configure a second DHCP address on an interface anyway. Please verify that it is correct.

s-makin

Thanks for taking the time to improve this documentation :)

I only have a small formatting nit - I'd like to remove the bullet list from the below section since it still reads just fine (and would render better) if it was just normal body text. If you'd rather keep the bullet list format, please add 2 spaces of indentation to the code blocks to make them part of the list items. I've left suggestions in line.

s-makin · 2026-01-12T10:25:18Z

docs/explanation/networking/configuring-networks.md

+
+#### Apply and verify the IP addresses
+
+- Apply the configuration to enable the virtual IP:


Suggested change

- Apply the configuration to enable the virtual IP:

Apply the configuration to enable the virtual IP:

s-makin · 2026-01-12T10:25:29Z

docs/explanation/networking/configuring-networks.md

+sudo netplan apply
+```
+
+- Verify the IP addresses are available locally using one or more of the following:


Suggested change

- Verify the IP addresses are available locally using one or more of the following:

Verify the IP addresses are available locally using one or more of the following:

s-makin · 2026-01-12T10:26:19Z

docs/explanation/networking/configuring-networks.md

+
+Check the output to see that the addresses were applied to the interface that was configured.
+
+- Verify the IP addresses are available on the network. From a different computer on the network:


Suggested change

- Verify the IP addresses are available on the network. From a different computer on the network:

Verify the IP addresses are available on the network. From a different computer on the network:

Apropos to all three suggestions: I removed the list formatting as suggested. You're right, it's cleaner and it matches other formatting better that way. New commits have been submitted.

TheJJ

I fear the multiple address syntax with labels is slightly wrong - i've added suggestions how to specify them correctly.

TheJJ · 2026-01-15T13:03:30Z

docs/explanation/networking/configuring-networks.md


+### Adding a virtual IP address
+
+Virtual IP is a method for broadcasting multiple IP addresses to the network *on a single network interface*. For example, configuring a single network interface, use virtual IP to:


Where does the name virtual come from? wouldn't this be just named "multiple ip addresses"? These IPs are real and allocated, so I wouldn't say there's something virtual (non-real) about them.

Honestly, I don't know. It's what I've always heard the technique called and it was the term used in the original issue without comment. I did some digging after your comment and I was surprised to find several sources that defined virtual IP as something completely different. I stand corrected 😔.

I have reworded several places referring to "multiple IPs" rather than "virtual IPs" (including the PR title). New commits have been submitted.

TheJJ · 2026-01-15T13:07:21Z

docs/explanation/networking/configuring-networks.md

+      addresses:
+      - 192.168.0.100/24
+        label: eno1:0
+      - 192.168.0.101/24
+        label: eno1:1


this syntax doesn't seem right.

Suggested change

addresses:

- 192.168.0.100/24

label: eno1:0

- 192.168.0.101/24

label: eno1:1

addresses:

- 192.168.0.99/24

- 192.168.0.100/24:

label: eno1:0

- 192.168.0.101/24:

label: eno1:some-label

I think the spacing got messed up pasting into my editor from my test setup. I've made the changes and submitted new commits.

TheJJ · 2026-01-15T13:09:17Z

docs/explanation/networking/configuring-networks.md

+      addresses:
+      - 192.168.0.101/24
+        label: eno1:1
+      dhcp4: true


same here:

Suggested change

addresses:

- 192.168.0.101/24

label: eno1:1

dhcp4: true

addresses:

- 192.168.0.101/24:

label: eno1:your-label

dhcp4: true

I think the spacing got messed up pasting into my editor from my test setup. I've made the changes and submitted new commits.

trinkel · 2026-01-26T00:13:40Z

Sorry for the delay getting back on these changes. I basically agree with everything, but somehow I busted my dev environment (see #615) and I can't review my work without starting from a fresh repo. Please bear with me as I get it straightened out.

TheJJ · 2026-01-26T14:19:33Z

I hope a git fetch origin; git rebase origin main would straighten things out for you, if not we can try to help :)

Apply suggestions from code review **configuring-networks.md** - Removed list formatting from `Apply and verify the IP addresses` section - This renders better and better matches formatting of the rest of the document

Apply suggestions from code review **configuring-networks.md** - Remove references to "virtual IP" and replace with "multiple IP addresses" - Change text to better describe a "multiple IP" environment

Apply suggestions from code review **configuring-networks.md** - Fix yaml formatting of configuration code - Add information to configuration code

**configuring-networks.md** - add `netplan` to list of testing options

**configuring-networks.md** - Remove `yaml` designator from code blocks to match the style of the rest of the document

trinkel · 2026-01-30T05:49:58Z

@s-makin, @TheJJ: Thanks for your editing and debugging suggestions. I synched my fork with upstream and re-cloned it locally. After cloning it a few times, it finally started working. Go figure.

I have made the changes and a few others in my local. I have a question since this is my first effort as part of a group: Is it considered rude to make suggested changes in my repo and committing rather than committing those suggestions in Github? I have other changes and wanted to have a record of the suggested changes in my repo history. But I also don't want to steal credit for making the suggestions (just not sure how all that works.)

Thanks again, and thanks for your patience.

trinkel · 2026-02-14T18:11:38Z

I have submitted new commits for these suggestions as well as some additional tweaking. Please let me know if I followed the correct conventions for doing this.

trinkel and others added 9 commits January 3, 2026 10:13

Add virtual IP section to Netplan Configuration

8f178c9

**configuring-networks.md** - Add section explaining how to add additional IPs to a typical network configuration.

Additional options for virtual IP

644ba2c

**configuring-networks.md** - Add `netplan` version with DHCP - Add note about DHCP limitation

Change grammar in virtual IP section (canonical#212)

e88cd16

**configuring-networks.md** - Minor grammar changes to three paragraphs.

Move virtual IP section to IP addressing section (canonical#212)

f6d1293

**configuring-networks.md** - Move _Adding a virtual IP address_ section - Was a level 2 heading under _Configuring networks_ - Now a level 3 heading under _IP Addressing_

Consolidate _Apply and verify_ sections (canonical#212)

af2e7d1

**configuring-networks.md** - Remove early apply and verify instructions from _Adding a virtual IP address_ section - Create a single _Apply and verify..._ section a conclusion to the _Adding a virtual IP address_ section

Minor text tweaks (canonical#212)

bc17c2f

**configuring-networks.md** - change look of code comments in _Adding a virtual IP_ section

Clarify uses for virtual ip

7046b60

**configuring-networks.md** - Add that virtual IP is used on single network interface - Fix wording of website virtual host usage

Merge branch 'canonical:main' into add-virtual-ip-configuration

00cadd9

Merge branch 'add-virtual-ip-configuration' of github.com:trinkel/ubu…

9711774

…ntu-server-documentation into add-virtual-ip-configuration

s-makin reviewed Jan 12, 2026

View reviewed changes

TheJJ requested changes Jan 15, 2026

View reviewed changes

Merge branch 'canonical:main' into add-virtual-ip-configuration

62d18b3

trinkel added 5 commits January 29, 2026 21:04

Remove list formatting from instruction section

38dd71b

Apply suggestions from code review **configuring-networks.md** - Removed list formatting from `Apply and verify the IP addresses` section - This renders better and better matches formatting of the rest of the document

Remove references to "virtual IP"

9c2ce68

Apply suggestions from code review **configuring-networks.md** - Remove references to "virtual IP" and replace with "multiple IP addresses" - Change text to better describe a "multiple IP" environment

Fix configuration formatting

e8b11d9

Apply suggestions from code review **configuring-networks.md** - Fix yaml formatting of configuration code - Add information to configuration code

Add configuration testing method

d0a0695

**configuring-networks.md** - add `netplan` to list of testing options

Remove code formatting

d7f6e12

**configuring-networks.md** - Remove `yaml` designator from code blocks to match the style of the rest of the document

trinkel changed the title ~~Add virtual ip to Network Configuration~~ Multiple IPs on single interface (Network Configuration) Jan 30, 2026

Merge branch 'canonical:main' into add-virtual-ip-configuration

2523875


		#### Apply and verify the IP addresses

		- Apply the configuration to enable the virtual IP:

	- Apply the configuration to enable the virtual IP:
	Apply the configuration to enable the virtual IP:

	- Verify the IP addresses are available locally using one or more of the following:
	Verify the IP addresses are available locally using one or more of the following:


		Check the output to see that the addresses were applied to the interface that was configured.

		- Verify the IP addresses are available on the network. From a different computer on the network:

	- Verify the IP addresses are available on the network. From a different computer on the network:
	Verify the IP addresses are available on the network. From a different computer on the network:


		### Adding a virtual IP address

		Virtual IP is a method for broadcasting multiple IP addresses to the network on a single network interface. For example, configuring a single network interface, use virtual IP to:

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trinkel commented Jan 12, 2026 • edited Loading Uh oh! There was an error while loading. Please reload this page.

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Description

Adds instructions for creating multiple IPs on a single interface to the network configuration documentation.

Related Issue

Partially fixes #212

Contributor License Agreement (CLA)

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trinkel commented Jan 12, 2026

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trinkel commented Jan 26, 2026

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