I do all
I cannot find any problem, even when I connect trough telnet from ssh, all ports connect successfully.
just when I use Port 25 it connect and close immediately.
[root@server1 bin]# telnet localhost 25
Trying ::1...
Connected to localhost.
Escape character is '^]'.
Connection closed by foreign host.
I checked domain by intodns.com and there is a problem:
Reverse MX A records (PTR)
ERROR: No reverse DNS (PTR) entries. The problem MX records are:
238.20.202.149.in-addr.arpa -> no reverse (PTR) detected
You should contact your ISP and ask him to add a PTR record for your ips
should I really contact ISP? Can I fix it?
Is the problem relevant to this problem?