I've been using OpenVPN client over vtun interface and all works as expected only if the remote VPN server name (in the OpenVPN config) is the IP address. When I use the DNS name as part of the OpenVPN config "remote" OpenVPN cannot establish connection.
The same hostname is being resolved correctly from the Edge Router box at the same time, when OpenVPN reports "openvpn[1381]: RESOLVE: Cannot resolve host address: SERVERNAMECOMESHERE Temporary failure in name resolution"
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It looks like for some reason OpenVPN cannot use DNS service or DNS query because they are forbidden in the default FW rules.
What I am missing?