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Kernel is very picky about accepting a route with "src" parameter.
The src address must have a corresponding local route, which it usually has when the IP address is added. Otherwise configuring it fails.
Say, you configure this profile:
nmcli connection add \
type ethernet \
con-name x \
autoconnect no \
ipv6.method disabled \
ipv4.method manual \
ipv4.addresses 10.0.0.1/24 \
ipv4.routes "10.0.0.0/24 src=10.0.0.1 table=5000"
ipv4.dad-timeout 500
this seems a sensible thing to do, because you want to use policy routing and add the device route to another table. Something similar might happen with
nmcli connection add \
type ethernet \
con-name x \
autoconnect no \
ipv6.method disabled \
ipv4.method manual \
ipv4.addresses 10.0.0.1/24 \
ipv4.route-table 5000 \
ipv4.routes "10.0.0.0/24 src=10.0.0.1"
ipv4.dad-timeout 500
(check both approaches, because they are not exactly the same!)
Anyway. With this, DAD/ACD is delaying the addition of the IPv4 address, and the IPv4 local route does not exist. At this point, the pref-src route cannot be added yet. What must happen, is that NM notices this, and retries later when the circumstances are right.
I guess, something similar could also happen with IPv6. Test that too!!
The underlying problem is because kernel tries to be overly helpful, and requiring that non-trivial relations between addresses/routes are honored. When it should just accept the configuration that the user wants to make. It's not that you couldn't configure wrong routing in kernel, this only captures a very very narrow case.
note that the pref-src could also be on *another* device/profile!! And that might be activated later (or never). It would seem, we need to keep such a route around, until we can configure it.
Since the problem described in this bug report should be
resolved in a recent advisory, it has been closed with a
resolution of ERRATA.
For information on the advisory (NetworkManager bug fix and enhancement update), and where to find the updated
files, follow the link below.
If the solution does not work for you, open a new bug report.
https://access.redhat.com/errata/RHBA-2023:6585
Kernel is very picky about accepting a route with "src" parameter. The src address must have a corresponding local route, which it usually has when the IP address is added. Otherwise configuring it fails. Say, you configure this profile: nmcli connection add \ type ethernet \ con-name x \ autoconnect no \ ipv6.method disabled \ ipv4.method manual \ ipv4.addresses 10.0.0.1/24 \ ipv4.routes "10.0.0.0/24 src=10.0.0.1 table=5000" ipv4.dad-timeout 500 this seems a sensible thing to do, because you want to use policy routing and add the device route to another table. Something similar might happen with nmcli connection add \ type ethernet \ con-name x \ autoconnect no \ ipv6.method disabled \ ipv4.method manual \ ipv4.addresses 10.0.0.1/24 \ ipv4.route-table 5000 \ ipv4.routes "10.0.0.0/24 src=10.0.0.1" ipv4.dad-timeout 500 (check both approaches, because they are not exactly the same!) Anyway. With this, DAD/ACD is delaying the addition of the IPv4 address, and the IPv4 local route does not exist. At this point, the pref-src route cannot be added yet. What must happen, is that NM notices this, and retries later when the circumstances are right. I guess, something similar could also happen with IPv6. Test that too!! The underlying problem is because kernel tries to be overly helpful, and requiring that non-trivial relations between addresses/routes are honored. When it should just accept the configuration that the user wants to make. It's not that you couldn't configure wrong routing in kernel, this only captures a very very narrow case.