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[solved] bogus default routes (dhcpcd)
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jamapii
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Joined: 16 Sep 2004
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PostPosted: Fri Aug 23, 2019 4:32 pm    Post subject: [solved] bogus default routes (dhcpcd) Reply with quote

Hello,

I found that when dhcpcd creates an IPv4 LL ip address (169.*), it also creates its own default route to nowhere.

That means internet connectivity goes down whenever an additional temporary interface is connected to do some work.

Networkmanager is not involved, i don't use it. netifrc is probably niot involved, as dhcpcd logs everything and seems to do this on its own.

The -L option can turn off IPv4LL, it's ok but overkill. -G prevents setting default routes.

Is there a way to just prevent setting bogus default routes, without turning off ipv4ll or default routes altogether?

thanks


Last edited by jamapii on Sat Dec 07, 2019 10:14 am; edited 1 time in total
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NeddySeagoon
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Joined: 05 Jul 2003
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PostPosted: Fri Aug 23, 2019 6:54 pm    Post subject: Reply with quote

jamapii,

The net scripts allow you to define several functions of your own choosing.
They always run but do nothing

You could use postup () to check for the IP address being Link Local and if so, delete the default route.
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NeddySeagoon

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UberLord
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Joined: 18 Sep 2003
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PostPosted: Sat Aug 24, 2019 7:30 pm    Post subject: Reply with quote

The route is not bogus:
https://tools.ietf.org/html/rfc3927#page-20

There is currently no means of disabling the default route only for IPv4LL while keeping it for DHCP.
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Use dhcpcd-ui (GTK+/Qt) as your System Tray Network tool
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jamapii
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Joined: 16 Sep 2004
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PostPosted: Sat Dec 07, 2019 10:14 am    Post subject: Reply with quote

I think then it is better to avoid ipv4ll when it is not really needed (that is, for me, basically always). And I think the most safe way here is to add

Code:
noipv4ll


to /etc/dhcpcd.conf.

Thanks a lot
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