Networking

Fedora now enables systemd-resolved service by default

With the enhancement, by enabling the systemd-resolved service by default, the GNU C Library (glibc) will perform name resolution using the nss-resolve module rather than the nss-dns module. Notable changes include:

  • systemd-resolved provides a system-level DNS cache that can substantially improve performance for applications that do not cache their own DNS results;

  • systemd-resolved allows correct handling of split DNS scenarios such as when VPNs are in use;

  • /etc/resolv.conf will now be managed by systemd-resolved rather than by NetworkManager;

  • /etc/resolv.conf will no longer be read when performing name resolution using glibc; however, it is still provided for compatibility with applications that manually read this file to perform name resolution;

  • Writing to /etc/resolv.conf will no longer work as expected.

NSS dbm support removal

Applications that use the Network Security Services (NSS) library often use a database for storing keys, certificates and trust. NSS supports two different storage formats:

  • SQLite

  • The dbm file format

Nowadays, NSS uses the SQLite file format by default and provides a transparent migration mechanism from dbm to SQLite.

The dbm file format has been deprecated since Fedora 28 due to various drawbacks, and from Fedora 33 dbm will not be supported.

This support removal will slightly reduce the size of the NSS library binary and the developers will be able to focus on the sole file format.