Linux Network Interface Naming - Revision history

Leo: updated content

2020-06-20T18:23:11Z

updated content

← Older revision		Revision as of 18:23, 20 June 2020
Line 1:		Line 1:
			Traditionally, network interfaces on Linux are enumerated as <code>eth[0...n]</code>, where the first device being probed on start up is assigned <code>eth0</code> and so on. Modern Linux utilizing systemd will assign network interfaces based on a [https://www.freedesktop.org/wiki/Software/systemd/PredictableNetworkInterfaceNames/ Predictable Network Interface naming scheme] which corresponds the network name to its hardware location. For example, an interface is named <code>wlp2p1</code> because it is a wireless device located at a PCI bus 2, slot 1. The motivation for this is to deterministically set network adapter names on systems with multiple adapters.

	== ~~Enabling old {{code\|eth0..N}} interface naming~~ ==		== Predictable Network Naming ==
	~~Modern Linux utilizing systemd names~~ network ~~interfaces after its physical location~~ to ~~ensure predictable network interface names~~ (eg. ~~{{code\|p2p1}} for PCI slot 1~~, ~~port 1). More information on this can be read at~~ https://~~www~~.~~freedesktop~~.~~org~~/~~wiki~~/~~Software~~/~~systemd~~/~~PredictableNetworkInterfaceNames~~/		Systems using the predictable network naming scheme will be named according to the following (simplified) rules. For the full description of these rules in greater detail, see the [https://access.redhat.com/documentation/en-us/red_hat_enterprise_linux/8/html/configuring_and_managing_networking/consistent-network-interface-device-naming_configuring-and-managing-networking Red Hat documentation for RHEL 8 on predictable network naming].
			{\| class="wikitable"
			\|+
			!Prefix
			!Suffix
			\|-
			\|
			* <code>en</code> - ethernet
			* <code>wl</code> - wireless LAN
			* <code>ww</code> - wireless wide area network
			\|
			* <code>o''N''</code> - onboard device, where N is the onboard index
			* <code>s''N''</code> - hot plug, where N is the slot index
			* <code>x''MAC''</code> - based on MAC address
			* <code>p''N''/s''X''</code> - for devices connected on a bus, where N is the bus number and X is the slot number.
			\|}
			For example: eno0 is the first onboard ethernet device, while enp0s0 is the first ethernet device connected to the first bus on the first slot.

	~~You can bring~~ back the ~~old naming scheme in one of three ways as outlined in the systemd page linked above:~~		==Revert back to the traditional {{code\|eth[0..N]}} naming scheme==
	~~# You disable the assignment of fixed names, so that the unpredictable kernel names are used again. For this, simply mask udev's~~ {{code\|.~~link}} file for the default policy: {{code\|ln -s /dev/null /etc/systemd/network/99-default~~.~~link~~}}		You can revert back the old naming scheme using any one of the following methods as outlined on [https://www.freedesktop.org/wiki/Software/systemd/PredictableNetworkInterfaceNames/ this systemd page].
	# You create your own manual naming scheme, for example by naming your interfaces "internet0", "dmz0" or "lan0". For that create your own {{code\|.link}} files in {{code\|/etc/systemd/network/}}, that choose an explicit name or a better naming scheme ~~for~~ one~~, some, or all~~ of ~~your interfaces. See {{code\|systemd.link(5)}} for more information.~~
	~~# You pass~~ the ~~{{code\|1=net~~.~~ifnames=0}} on the kernel command line~~. ~~Do this by editing {{code\|~~/~~etc~~/~~default~~/~~grub}}, then applying it with {{code\|grub2-mkconfig -o~~ /~~boot~~/~~grub2/grub.cfg}} before rebooting~~.

	~~== Renumbering~~ network ~~interfaces ==~~		#You create your own manual naming scheme by creating your own <code>''custom''.link</code> files within <code>/etc/systemd/network/</code> which defines the specific name you wish to use. The description for this file is outlined at https://www.freedesktop.org/software/systemd/man/systemd.link.html<nowiki/>{{Highlight
	Do you ~~have network interfaces that no longer start~~ at ~~0 (eg~~: {{~~code~~\|~~eth0}}, {{~~code~~\|em1}}, {{code\|eth1000}}~~)~~? Interface numberings are defined through udev rules~~. ~~To reset the numbers starting at~~ 0~~, any old interfaces that was previously found by udev needs to be cleared.~~		\| code = # Match based on MAC address (and device path if uncommented)
			[Match]
			MACAddress=00:a0:de:63:7a:e6
			# Path=pci-0000:02:00.0-*

	~~To renumber~~ the ~~interfaces~~, ~~you can edit~~ the ~~udev rules at~~ {{code\|~~/etc/udev/rules.d/70-persistent-~~net.~~rules~~}}~~. Remove lines defining~~ the ~~extraneous interfaces that you don't want~~. ~~Once done, ensure that your~~ network ~~configs are matches up to your new network interface~~ names. ~~(Red Hat based~~ only)		# Link properties
	{{~~highlight~~\|~~lang~~=~~text~~\|~~code=~~		[Link]
	# cd /etc/~~sysconfig~~/network-~~scripts~~/		Name=eth0
	# ls ifcfg*		\| lang = text
	}}		}} In the example above, the device matching the given MAC address will have its name set to eth0.
			#You pass {{code\|1=net.ifnames=0}} to the kernel on boot by setting it in the boot loader. This is not recommended on systems with multiple network interfaces as they may be assigned names inconsistently across reboots. This should be safe on systems with only one network adapter. You set this kernel argument this by editing {{code\|/etc/default/grub}}, appending <code>net.ifnames=0</code> to the kernel command line, applying it with {{code\|grub2-mkconfig -o /boot/grub2/grub.cfg}}, and then rebooting.
			#You disable the assignment of fixed names by symlinking <code>/etc/systemd/network/99-default.link</code> to <code>/dev/null</code> and rebuilding initrd.

	~~Once completed~~, ~~reboot~~ the ~~machine~~.		==Renumbering network interfaces==
			If your system is relying on udev rather than systemd-udevd (and thereby using systemd's predictable network interfacing naming scheme), after inserting and removing network interfaces, your network interface now has a non-zero number. For example, after inserting and replacing a network interface twice, the primary interface is now named <code>eth2</code>. Systems affected by this problem includes RHEL 6 or prior.

	~~== See Also ==~~		To rename interfaces so that it starts back at <code>eth0</code>, edit the udev rules defined in {{code\|/etc/udev/rules.d/70-persistent-net.rules}}. Remove lines defining the extraneous interfaces that you don't want. Once done, ensure that your network configs in <code>/etc/sysconfig/network-scripts/</code> matches up to your new network interface names.
	* [[Udev Rules]]

	{{Navbox Linux}}[[Category:Linux]]		Reboot to apply.

			==See Also==

			*[[Udev Rules]]
			*https://access.redhat.com/solutions/2435891
			*https://access.redhat.com/documentation/en-us/red_hat_enterprise_linux/7/html/networking_guide/ch-consistent_network_device_naming
			*https://access.redhat.com/documentation/en-us/red_hat_enterprise_linux/8/html/configuring_and_managing_networking/consistent-network-interface-device-naming_configuring-and-managing-networking

			{{Navbox Linux}}
			[[Category:Linux]]

Leo at 21:28, 10 March 2020

2020-03-10T21:28:59Z

← Older revision		Revision as of 21:28, 10 March 2020
Line 1:		Line 1:
	~~Do you have network interfaces that no longer start at 0 (eg: eth0, em1, etc...)?~~

	== ~~Edit udev Rules~~ ==		== Enabling old {{code\|eth0..N}} interface naming ==
	~~To renumber the~~ interfaces, ~~you~~ can ~~edit~~ the udev ~~rules at~~:		Modern Linux utilizing systemd names network interfaces after its physical location to ensure predictable network interface names (eg. {{code\|p2p1}} for PCI slot 1, port 1). More information on this can be read at https://www.freedesktop.org/wiki/Software/systemd/PredictableNetworkInterfaceNames/
	{{~~highlight~~\|~~lang=text~~\|code=
	/etc/~~udev~~/~~rules.d/70~~-~~persistent~~-~~net~~.~~rules~~		You can bring back the old naming scheme in one of three ways as outlined in the systemd page linked above:
	}}		# You disable the assignment of fixed names, so that the unpredictable kernel names are used again. For this, simply mask udev's {{code\|.link}} file for the default policy: {{code\|ln -s /dev/null /etc/systemd/network/99-default.link}}
			# You create your own manual naming scheme, for example by naming your interfaces "internet0", "dmz0" or "lan0". For that create your own {{code\|.link}} files in {{code\|/etc/systemd/network/}}, that choose an explicit name or a better naming scheme for one, some, or all of your interfaces. See {{code\|systemd.link(5)}} for more information.
			# You pass the {{code\|1=net.ifnames=0}} on the kernel command line. Do this by editing {{code\|/etc/default/grub}}, then applying it with {{code\|grub2-mkconfig -o /boot/grub2/grub.cfg}} before rebooting.

	~~Remove lines defining the extraneous~~ interfaces that ~~you don't want~~. ~~Once done~~, ~~ensure~~ that ~~your network configs are correct (Red Hat based only)~~		== Renumbering network interfaces ==
			Do you have network interfaces that no longer start at 0 (eg: {{code\|eth0}}, {{code\|em1}}, {{code\|eth1000}})? Interface numberings are defined through udev rules. To reset the numbers starting at 0, any old interfaces that was previously found by udev needs to be cleared.

			To renumber the interfaces, you can edit the udev rules at {{code\|/etc/udev/rules.d/70-persistent-net.rules}}. Remove lines defining the extraneous interfaces that you don't want. Once done, ensure that your network configs are matches up to your new network interface names. (Red Hat based only)
	{{highlight\|lang=text\|code=		{{highlight\|lang=text\|code=
	# cd /etc/sysconfig/network-scripts/		# cd /etc/sysconfig/network-scripts/
Line 14:		Line 17:
	}}		}}

	~~Ensure the scripts matches up to the interfaces you defined in the udev rules.~~ Once completed, reboot the machine.		Once completed, reboot the machine.


	== See Also ==		== See Also ==

Leo: Leo moved page Renaming / Renumbering Network Interfaces to Linux Network Interface Naming: Adding more info to network interfaces in general

2020-03-10T21:20:35Z

Leo moved page Renaming / Renumbering Network Interfaces to Linux Network Interface Naming: Adding more info to network interfaces in general

← Older revision		Revision as of 21:20, 10 March 2020
(No difference)

Leo: formatting

2019-09-12T05:48:01Z

formatting

← Older revision		Revision as of 05:48, 12 September 2019
Line 2:		Line 2:

	== Edit udev Rules ==		== Edit udev Rules ==

	To renumber the interfaces, you can edit the udev rules at:		To renumber the interfaces, you can edit the udev rules at:
	/etc/udev/rules.d/70-persistent-net.rules		{{highlight\|lang=text\|code=
			/etc/udev/rules.d/70-persistent-net.rules
			}}

	Remove lines defining the extraneous interfaces that you don't want. Once done, ensure that your network configs are correct (~~RedHat~~ based only)		Remove lines defining the extraneous interfaces that you don't want. Once done, ensure that your network configs are correct (Red Hat based only)

	cd /etc/sysconfig/network-scripts/		{{highlight\|lang=text\|code=
	ls ifcfg*		# cd /etc/sysconfig/network-scripts/
			# ls ifcfg*
			}}

	Ensure the scripts matches up to the interfaces you defined in the udev rules. Once completed, reboot the machine.		Ensure the scripts matches up to the interfaces you defined in the udev rules. Once completed, reboot the machine.

Leo: Text replacement - "Category:Linux{{Navbox Linux}}" to "{{Navbox Linux}}Category:Linux"

2019-09-01T06:20:42Z

Text replacement - "Category:Linux{{Navbox Linux}}" to "{{Navbox Linux}}Category:Linux"

← Older revision		Revision as of 06:20, 1 September 2019
Line 17:		Line 17:
	* [[Udev Rules]]		* [[Udev Rules]]

	[[Category:Linux]]~~{{Navbox Linux}}~~		{{Navbox Linux}}[[Category:Linux]]

Leo: Text replacement - "{{Navbox Linux}}{{Navbox Linux}}" to "{{Navbox Linux}}"

2019-09-01T05:10:34Z

Text replacement - "{{Navbox Linux}}{{Navbox Linux}}" to "{{Navbox Linux}}"

← Older revision		Revision as of 05:10, 1 September 2019
Line 17:		Line 17:
	* [[Udev Rules]]		* [[Udev Rules]]

	[[Category:Linux]]~~{{Navbox Linux}}~~{{Navbox Linux}}		[[Category:Linux]]{{Navbox Linux}}

Leo: Text replacement - "Category:Linux" to "Category:Linux{{Navbox Linux}}"

2019-09-01T05:08:47Z

Text replacement - "Category:Linux" to "Category:Linux{{Navbox Linux}}"

← Older revision		Revision as of 05:08, 1 September 2019
Line 17:		Line 17:
	* [[Udev Rules]]		* [[Udev Rules]]

	[[Category:Linux]]{{Navbox Linux}}		[[Category:Linux]]{{Navbox Linux}}{{Navbox Linux}}

Leo: Text replacement - "{{Navbox Linux}} {{Navbox Linux}}" to "{{Navbox Linux}}"

2019-09-01T04:46:07Z

Text replacement - "{{Navbox Linux}} {{Navbox Linux}}" to "{{Navbox Linux}}"

← Older revision		Revision as of 04:46, 1 September 2019
Line 18:		Line 18:

	[[Category:Linux]]{{Navbox Linux}}		[[Category:Linux]]{{Navbox Linux}}


	~~{{Navbox Linux}}~~

Leo: Text replacement - "Category:Linux " to "Category:Linux{{Navbox Linux}} "

2019-09-01T03:20:36Z

Text replacement - "Category:Linux " to "Category:Linux{{Navbox Linux}} "

← Older revision		Revision as of 03:20, 1 September 2019
Line 17:		Line 17:
	* [[Udev Rules]]		* [[Udev Rules]]

	[[Category:Linux]]		[[Category:Linux]]{{Navbox Linux}}


	{{Navbox Linux}}		{{Navbox Linux}}

Leo at 06:20, 29 March 2015

2015-03-29T06:20:38Z

← Older revision		Revision as of 06:20, 29 March 2015
Line 12:		Line 12:

	Ensure the scripts matches up to the interfaces you defined in the udev rules. Once completed, reboot the machine.		Ensure the scripts matches up to the interfaces you defined in the udev rules. Once completed, reboot the machine.


			== See Also ==
			* [[Udev Rules]]

	[[Category:Linux]]		[[Category:Linux]]


			{{Navbox Linux}}