By ‘DNS failover’ I take it you mean DNS Round Robin combined with some monitoring, i.e. publishing multiple IP addresses for a DNS hostname, and removing a dead address when monitoring detects that a server is down. This can be workable for small, less trafficked websites. By design, when you answer a DNS request you … Read more
A glue record is a term for a record that’s served by a DNS server that’s not authoritative for the zone, to avoid a condition of impossible dependencies for a DNS zone. Say I own a DNS zone for example.com. I want to have DNS servers that’re hosting the authoritative zone for this domain so … Read more
I would choose a consistent approach across the entire environment. Both solutions work fine and will remain compatible with most applications. There is a difference in manageability, though. I go with the short name as the HOSTNAME setting, and set the FQDN as the first column in /etc/hosts for the server’s IP, followed by the … Read more
v=spf1 include:_spf.google.com include:otherdomain.com ~all There’s no restriction against including multiple names in a single entry; Hotmail, for instance, takes this to extremes. Note that multiple includes, or nested ones, need to stay under the limit of 10 total DNS lookups for the whole SPF check.
Answer The short answer to your specific question of listing CNAMEs is that you cannot without permission to do zone transfers (see How to list all CNAME records for a given domain?). That said, if your company’s DNS server still supports the ANY query, you can use dig to list the other records by doing: … Read more
Dig will also do it quite nicely: dig -t txt example.com and if you add the +short option you get just the txt record in quote marks with no other cruft.
ping -a w.x.y.z Should resolve the name from the IP address if the reverse lookup zone has been set up properly. If the reverse lookup zone does not have an entry for the record, the -a will just ping without a name.