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source-validation will be configured at different locations and could lead to massiv confusion
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Description

hi.

after working on T2059 I had took a deeper look into it confused how source-validation is set . In the moment there are two different way's to configure source-validation:

  1. vyatta-cfg-firewall (/opt/vyatta/share/vyatta-cfg/templates/firewall/source-validation/node.def)
  2. vyatta-cfg-quagga: (/opt/vyatta/share/vyatta-cfg/templates/interfaces/*/node.tag/ip/source-validation/node.def)

In vyatta-cfg-firewall all Interfaces and the all interfacces is configured.
In vyatta-cfg-quagga it's only configured at interface level

The default behavior is unconfigured.

sysctl.txt from the kernel documentation say's:

rp_filter - INTEGER
	0 - No source validation.
	1 - Strict mode as defined in RFC3704 Strict Reverse Path
	    Each incoming packet is tested against the FIB and if the interface
	    is not the best reverse path the packet check will fail.
	    By default failed packets are discarded.
	2 - Loose mode as defined in RFC3704 Loose Reverse Path
	    Each incoming packet's source address is also tested against the FIB
	    and if the source address is not reachable via any interface
	    the packet check will fail.

	Current recommended practice in RFC3704 is to enable strict mode
	to prevent IP spoofing from DDos attacks. If using asymmetric routing
	or other complicated routing, then loose mode is recommended.

	The max value from conf/{all,interface}/rp_filter is used
	when doing source validation on the {interface}.

	Default value is 0. Note that some distributions enable it
	in startup scripts.

Especially:

	The max value from conf/{all,interface}/rp_filter is used
	when doing source validation on the {interface}.

looks like that the current system makes it very confused. Then there is also:

net.ipv4.conf.default.rp_filter:

conf/default/*: Change the interface-specific default settings.
conf/all/*: Change all the interface-specific settings.

I thing we should discuss how we can handle this better and more understandable for the users.

Details

Difficulty level
Unknown (require assessment)
Version
1.2.4
Why the issue appeared?
Will be filled on close
Is it a breaking change?
Config syntax change (migratable)

Event Timeline

rherold created this task.Feb 21 2020, 9:37 AM
rherold created this object in space S1 VyOS Public.
pasik added a subscriber: pasik.Mar 30 2020, 7:10 AM