014.01.40.5. What are the challenges with the traditional DNS configuration, and how are they addressed through caching and zero-configuration DNS solutions? Name a few daemons commonly used for DNS caching.
The challenges with traditional DNS configuration are:-
The local machine does not name cache server replies, so frequent repeated network access may be unnecessarily slow due to name server requests. To resolve this, many machines run an intermediate daemon to intercept name server requests and cache the reply and use cached answers if possible. The most common of the daemons used is systemd-resolved, others are dnsmasq or nscd. We can also use BIND(the standard UNIX name server daemon) as a cache.
The second one is with the traditional name server setup: it can be particularly inflexible if you want to be able to look up names on your local network without messing with a lot of configuration. For e.g., while setting up a network appliance on our network, we want to call it by name immediately. This is the idea behind multicast DNS(mDNS) and Link Local Multicast Name Resolution(LLMNR). IF process wants to find a host by name on the local network, it just broadcasts a request over the network, if present, the target host replies with its address.
Traditional DNS configurations face challenges, such as slow network access due to the lack of local caching of server replies. To overcome this, many systems employ intermediate daemons like systemd-resolved, dnsmasq, or nscd to intercept and cache name server requests, optimizing repeated access.
Another challenge arises in traditional setups when local network name lookups become inflexible and require extensive configuration. For instance, setting up a network appliance might need immediate name recognition. This led to the development of multicast DNS (mDNS) and Link Local Multicast Name Resolution (LLMNR), allowing devices to broadcast name requests over the network, receiving prompt replies from target hosts without intricate configurations.
