The current problem seems to be that the nameserver is not reachable on port 53: Code: thom@Thoms-MBP dir % telnet 2.186.123.193 53 Trying 2.186.123.193... telnet: connect to address 2.186.123.193: Operation timed out telnet: Unable to connect to remote host So check your firewall.
Telnet won't work here since DNS is UDP-based and not TCP. OP may better use netcat/nc to check if the port is reachable by executing: Code: nc -u <host> <port>
I deleted all and recreated again to find the problem but the issue persists. the funny thing is that when go with ns1.iibi.ir can reach the Apache web server.
No. What @Th0m checked is if the server with the IP 2.186.123.193, which is your nameserver, is connectable on port 53 and it still is not. You don't need any zones/records to test this. We can't connect from external locations to your DNS server on port 53, which means it's not gonna work. So either within ISPConfig in the configuration for the system, you did not open port 53 for your DNS servers or any firewall in between your server and the internet is not letting that traffic through - or the DNS server isn't running at all.
Have you checked with web tools like intodns.com, https://zonecheck.org/zonemaster/ and similar what errors your dns zone currently has?
appreciate guys, the problem is solved. due to new settings applied in ISP, some ports such as 53 were closed. Appreciate your help.
