For several days now, after several reboots I still am faced with the issue of my
CentOS 7 machine not being able to ping my domain.
[root@ip126 ~]# ping sub.mydomain.eu ping: sub.mydomain.eu: Name or service not known
How am I able to clear whatever cache is preventing me from connecting to this address?
sub.mydomainand the phrasing
ping my domain, you distract readers. Is your domain externally resolvable? If it's not private data, you could provide the actual domain name; otherwise, more details about your nameserver setup (/etc/resolv.conf) and which DNS servers you think should be able to answer the query.
dig sub.mydomain.eu. Your machine should not cache dns across boots: The time to live is, usually, to short to make it worth while.
dig sub.mydomain.eu @188.8.131.52work?