Postfix - puerto 25 cerrado

[yalta]

The SYN Stealth Scan took 53 seconds to scan 1601 ports.
Interesting ports on (200.82.64.77):
(The 1582 ports scanned but not shown below are in state: closed)
Port State Service
22/tcp open ssh
23/tcp open telnet
25/tcp filtered smtp
53/tcp filtered domain
80/tcp open http
110/tcp open pop-3
111/tcp filtered sunrpc
135/tcp filtered loc-srv
139/tcp filtered netbios-ssn
443/tcp filtered https
445/tcp filtered microsoft-ds
593/tcp filtered http-rpc-epmap
901/tcp filtered samba-swat
3128/tcp filtered squid-http
3306/tcp filtered mysql
4444/tcp filtered krb524
4480/tcp filtered proxy-plus
6588/tcp filtered analogx
8080/tcp filtered http-proxy

Nmap run completed -- 1 IP address (1 host up) scanned in 53 seconds
[root@dnl]#

el puerto 25 esta filtrado
y el telnet abierto nada seguro