sonic-buildimage/files/image_config/resolv-config
Oleksandr Ivantsiv 5ef488f808 Clear DNS configuration received from DHCP during networking reconfiguration in Linux. (#13516)
- Why I did it
fixes #12907

When the management interface IP address configuration changes from dynamic to static the DNS configuration (retrieved from the DHCP server) in /etc/resolv.conf remains uncleared. This leads to a DNS configuration pointing to the wrong nameserver. To make the behavior clear DNS configuration received from DHCP should be cleared.

- How I did it
Use resolvconf package for managing DNS configuration. It is capable of tracking the source of DNS configuration and puts the configuration retrieved from the DHCP servers into a separate file. This allows the implementation of DNS configuration cleanup retrieved from DHCP during networking reconfiguration.

- How to verify it
Ensure that the management interface has no static configuration.
Check that /etc/resolv.conf has DNS configuration.
Configure a static IP address on the management interface.
Verify that /etc/resolv.conf has no DNS configuration.
Remove the static IP address from the management interface.
Verify that /etc/resolv.conf has DNS configuration retrieved form DHCP server.
2023-02-16 18:36:33 +08:00
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resolv.conf.head Clear DNS configuration received from DHCP during networking reconfiguration in Linux. (#13516) 2023-02-16 18:36:33 +08:00