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sysctl.d: switch net.ipv4.conf.all.rp_filter from 1 to 2#10971

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poettering merged 1 commit intosystemd:masterfrom
NetworkManager:lr/strict-rp-filter-makes-us-all-sad
Nov 28, 2018
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sysctl.d: switch net.ipv4.conf.all.rp_filter from 1 to 2#10971
poettering merged 1 commit intosystemd:masterfrom
NetworkManager:lr/strict-rp-filter-makes-us-all-sad

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@lkundrak
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This switches the RFC3704 Reverse Path filtering from Strict mode to Loose
mode. The Strict mode breaks some pretty common and reasonable use cases,
such as keeping connections via one default route alive after another one
appears (e.g. plugging an Ethernet cable when connected via Wi-Fi).

The strict filter also makes it impossible for NetworkManager to do
connectivity check on a newly arriving default route (it starts with a
higher metric and is bumped lower if there's connectivity).

Kernel's default is 0 (no filter), but a Loose filter is good enough. The
few use cases where a Strict mode could make sense can easily override
this.

The distributions that don't care about the client use cases and prefer a
strict filter could just ship a custom configuration in
/usr/lib/sysctl.d/ to override this.

This switches the RFC3704 Reverse Path filtering from Strict mode to Loose
mode. The Strict mode breaks some pretty common and reasonable use cases,
such as keeping connections via one default route alive after another one
appears (e.g. plugging an Ethernet cable when connected via Wi-Fi).

The strict filter also makes it impossible for NetworkManager to do
connectivity check on a newly arriving default route (it starts with a
higher metric and is bumped lower if there's connectivity).

Kernel's default is 0 (no filter), but a Loose filter is good enough. The
few use cases where a Strict mode could make sense can easily override
this.

The distributions that don't care about the client use cases and prefer a
strict filter could just ship a custom configuration in
/usr/lib/sysctl.d/ to override this.
@keszybz
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keszybz commented Nov 28, 2018

LGTM.

@keszybz
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keszybz commented Nov 28, 2018

Bonus points for the branch name ;)

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3 participants