Bridge - Revision history

Prabuanand: added {{Template:Accuracy}} to check {{ic|brctl}} package

2025-08-15T06:06:31Z

added {{Template:Accuracy}} to check {{ic|brctl}} package

← Older revision		Revision as of 06:06, 15 August 2025
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	== Using brctl ==		== Using brctl ==

			{{Template:Accuracy\|Package {{pkg\|bridge}} uses {{ic\|brctl}} command. To verify if this needs {{pkg\|bridge-utils}} instead of the version from [[Busybox]].\|section=Using brctl}}

	Bridges can be managed manually with the {{ic\|brctl}} command from the {{pkg\|bridge-utils}} package.		Bridges can be managed manually with the {{ic\|brctl}} command from the {{pkg\|bridge-utils}} package.

2025-07-22T17:07:22Z

applied wikitags, moved deprecated brctl to bottom of the page and removed obsolete note

2025-07-21T22:08:41Z

Setting MTU =

← Older revision		Revision as of 22:08, 21 July 2025
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	== Setting MTU ===		== Setting MTU ==

	It can be a bit tricky to set the MTU on the bridge and child interfaces.		It can be a bit tricky to set the MTU on the bridge and child interfaces.
	~~This~~ is tested:		That applies to both the bridge-utils and bridge packages.

			The below is tested (10g ports only used as a bridge and not connected to host. you can work from there and make more complex/capable setups. don't forget to consider OVS instead)

	<pre>		<pre>

2025-07-21T22:07:30Z

← Older revision		Revision as of 22:07, 21 July 2025
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	tshark -i eth0 -Y "bootp.option.type == 53"		tshark -i eth0 -Y "bootp.option.type == 53"
	</pre>		</pre>



			== Setting MTU ===

			It can be a bit tricky to set the MTU on the bridge and child interfaces.
			This is tested:

			<pre>
			buildfinity:~$ cat /etc/network/interfaces
			auto lo
			iface lo inet loopback

			# "management / oob port"
			auto eth0
			iface eth0 inet dhcp
			ip_rp_filter 2 # only relevant when you set an ip on br0


			iface eth1 inet manual
			iface eth2 inet manual
			iface eth3 inet manual
			iface eth4 inet manual
			iface eth5 inet manual
			iface eth6 inet manual
			iface eth7 inet manual
			iface eth8 inet manual

			auto br0
			iface br0 inet manual
			bridge-ports eth1 eth2 eth3 eth4 eth5 eth6 eth7 eth8
			bridge-stp on
			bridge-fd 2
			bridge-bridgeprio 32768
			pre-up ip link set dev eth1 mtu 9000
			pre-up ip link set dev eth2 mtu 9000
			pre-up ip link set dev eth3 mtu 9000
			pre-up ip link set dev eth4 mtu 9000
			pre-up ip link set dev eth5 mtu 9000
			pre-up ip link set dev eth6 mtu 9000
			pre-up ip link set dev eth7 mtu 9000
			pre-up ip link set dev eth8 mtu 9000
			post-up ip link set dev br0 mtu 9000
			</pre>

			So we have a three stage process:

			1. bring up member interfaces
			2. set up bridge, first run all pre-up commands, setting the MTU of the members
			3. once bridge is up, set its own mtu

2023-07-29T06:30:58Z

Changed a hyperlink to its canonical URL.

← Older revision		Revision as of 06:30, 29 July 2023
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	[[Category:Networking]]		[[Category:Networking]]
	This document describes how to configure a [~~http~~://en.wikipedia.org/wiki/~~Bridging_%28networking%29~~ network bridge] interface in Alpine Linux.		This document describes how to configure a [https://en.wikipedia.org/wiki/Network_bridge network bridge] interface in Alpine Linux.

	== Using brctl ==		== Using brctl ==

2022-08-15T17:49:30Z

Bridging for a Xen dom0: formatting

← Older revision		Revision as of 17:49, 15 August 2022
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	At bridge creation time, the virtual interface does not exist and will be added by the Xen toolstack when a domU is booting (see Xen documentation on how to link the virtual interface to the correct bridge).		At bridge creation time, the virtual interface does not exist and will be added by the Xen toolstack when a domU is booting (see Xen documentation on how to link the virtual interface to the correct bridge).

	;Particulars :		'''Particulars:'''
	- the bridge consists of a single physical interface ~~<br/>~~		* the bridge consists of a single physical interface
	- the physical interface does not have an IP and is configured manually ~~<br/>~~		* the physical interface does not have an IP and is configured manually
	- the bridge will have the IP address and will be auto, resulting in bringing up the physical interface ~~<br/>~~		* the bridge will have the IP address and will be auto, resulting in bringing up the physical interface

	This translates to a sample config :		This translates to a sample config ''/etc/network/interfaces''

	~~Example~~ ''/etc/network/interfaces'':

	<pre>		<pre>

2022-08-15T17:47:19Z

Using brctl: mention that bridge-utils is deprecated

← Older revision		Revision as of 17:47, 15 August 2022
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	== Using brctl ==		== Using brctl ==

			{{Obsolete\|According to [https://wiki.linuxfoundation.org/networking/bridge upstream], ''bridge-utils'' is deprecated. Please use ''bridge'' instead.}}

	Bridges are managed manually with the '''brctl''' command.		Bridges are managed manually with the '''brctl''' command.
	<pre>		<pre>

2022-08-15T17:41:18Z

Little script to allow dhcp over iptables: remove no-operation script

← Older revision		Revision as of 17:41, 15 August 2022
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	<pre>		<pre>
			# Run local.d scripts on boot.
	rc-update add local		rc-update add local
	~~</pre>~~

	~~<pre>~~		# Write the script.
	cat >> /etc/local.d/iptables_dhcp_kvm.start << EOM		cat >> /etc/local.d/iptables_dhcp_kvm.start << EOM
	echo 0 > /proc/sys/net/bridge/bridge-nf-call-arptables		echo 0 > /proc/sys/net/bridge/bridge-nf-call-arptables
Line 172:		Line 172:
	exit 0		exit 0
	EOM		EOM
	~~</pre>~~

	~~<pre>~~		# local.d script must be executable.
	~~cat >> /etc/~~local.d~~/iptables_dhcp_kvm~~.~~stop << EOM~~		chmod a+x /etc/local.d/iptables_dhcp_kvm.start
	~~exit 0~~
	~~EOM~~
	~~</pre>~~

	~~<pre>~~
	chmod +x /etc/local.d/iptables_dhcp_kvm.*
	</pre>		</pre>

2022-08-15T17:37:23Z

remove references to "older versions" of alpine. 2.4 is last released 2012, alpine project doesn't support it, nor should we

← Older revision		Revision as of 17:37, 15 August 2022
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	== Configuration file ==		== Configuration file ==
	~~{{Note\|This requires Alpine Linux v2.4 or newer}}~~
	Install the scripts that configure the bridge.		Install the scripts that configure the bridge.
	{{Cmd\|apk add bridge}}		{{Cmd\|apk add bridge}}
Line 78:		Line 77:

	== Using pre-up/post-down ==		== Using pre-up/post-down ==
	~~For older versions of Alpine Linux, or if~~ you want be able to control the bridge interfaces individually, you need to use pre-up/post-down hooks.		If you want be able to control the bridge interfaces individually, you need to use pre-up/post-down hooks.

	Example ''/etc/network/interfaces'':		Example ''/etc/network/interfaces'':

2022-08-15T17:35:19Z

Configuration file: make it more clean one should '''not''' set addresses on bridge members, only on the bridge itself

← Older revision		Revision as of 17:35, 15 August 2022
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	Bridging is then configured in ''/etc/network/interfaces'' with the ''bridge-ports'' keyword.		Bridging is then configured in ''/etc/network/interfaces'' with the ''bridge-ports'' keyword.
	~~Note:~~ You normally don't assign ip addresses to the bridged interfaces (eth0 and eth1 in our example) but to the bridge itself (br0).		{{Warning\|You normally don't assign ip addresses to the bridged interfaces (eth0 and eth1 in our example) but to the bridge itself (br0).}}

	In this example the address 192.168.0.1/24 is used.		In this example the address 192.168.0.1/24 is used.