[knot-dns-users] Warning - TCP ports binding in Knot DNS versions 3.0.0 and 3.0.1

Hello Knot DNS users! We would like to inform you about a change in Knot DNS behaviour in versions 3.0.0 and 3.0.1. These two versions don't allow sharing of TCP ports between programs, including other knotd instances (SO_REUSEADDR isn't set). While this behaviour is better from point of view of security, the downside of it is that when restarting a knotd daemon, binding to a TCP port may fail after a restart if the restart is immediate. In such a case, an error is logged and Knot starts its operation on other configured ports only. To verify that all TCP ports have been bound successfully after Knot restart, please always check the log for possible errors. Such errors would be close to the initial message about Knot DNS starting. Since there was a complaint about this change, we plan to re-enable TCP ports reuse in future releases. We also ponder making knotd exit if it fails to bind to any of configured TCP ports. We would like hear from you whether such a behaviour is what you, users, want best. Please, let us know if you prefer this or a different solution. With regards, David Vašek CZ.NIC