Hello all,
I have
Operating system CentOS Linux 6.8
Webmin version 1.801 &
Virtualmin version 5.03.gpl
All packages are uptodate.
When i added a new server today, I start getting this error in DNS records for some servers
Warning - errors were found in this domain’s DNS records : NS record ns1.maindomain.com. cannot be resolved to an IP address
Also in DNS records, previously there used to be 2 ns records like ns1.maindomain.com and ns2.maindomain.com
but now its just ns.maindomain.com
Short answer: You need to have a FQDN configured correctly with 2 parent name servers and YOUR name servers need to be published by your FQDN-zone.
Long answer:
DNS is a bit of a hassle but for a working setup you need to do the following:
Your top domain must have at least 2 parent name servers to spread the word on the internet about your zone. Most registrars offer this but you can use other name servers as well. The parent name servers are outside your domain, preferably located on different geographical locations.
So, you registered yourdomain.example with example.com, example.com provides 2 name servers that are already known by the internet like: ns1.example.com and ns2.example.com.
After a while your zone is up, you can speedup this process by taking care that there is a server listening to requests made to the domain. Most of the time a domain can be up within everything between 5 minutes and 2 days.
Register you yourdomain.example with a zone management service so you can add records like www in A 127.0.0.1 (Use public IP addresses in your public top zone) If your registrar doesn’t have a record management interface consider Hurricane Electric or some other DNS-zone management system for yourdomain.example
make the following records in yourdomain.example:
server1.yourdomain.example IN A 300 {first public IP of your master DNS server} - and
server2.yourdomain.example IN A 300 {second public IP of your secondary DNS server} (preferably different public IP’s else you get errors when checking)
The IN A means that it converts the name to the IP, the 300 is the Time To Live of your record in seconds. First use 300, when sure everything is OK, set to something like 14400 seconds at least. This will save you time when you make errors.
Optional: Ask the provider which gave you the IP addresses of server1 and server2 to make a PTR (reverse IP to name) records for consistency of the zone, some providers allow you to manage this yourself.
See this tutorial about how to make your secondary server listen to and mirror your master server using Virtualmin/Webmin: Here
Register new domains you wish to host with your own namer servers, server1.yourdomain.example and server2.yourdomain.example first, and then buy the domains from a registrar where you can set your own name servers. Keep the TTL for a new zone at 300s until you’re sure it’s working correct.
Try http://aws.amazon.com if you need a free second server for a year (the smallest virtual instance normally costs about 44 euro’s a year after your free tier ends), and you can host yourdomain.example zone with Amazon Route53 for a very small fee. ((Prepaid) Credit card needed)
So: Your domain has 2 parents and is managed by those parents. And it contains 2 childs which will be your name servers.
Your childs are resp. master and slave Virtualmin/BIND.
Zones you make on server1 are replicated to server2.
This is the correct way to manage DNS-servers yourself for your other domains you may add to the servers.
but previously the virtualmin set it itself. i am not a techie so i followed the basic virtualmin tutorial and it set everything up for me, this time its shpwing this error. however my domains are working fine.