Host eintragen in /etc/hosts:
IP_ADRESS HOST_NAME
IP_ADRESS localhost
Auskommentieren:
127.0.1.1 HOST_NAME
127.0.1.1 localhost

Port freigeben:

$ su --login
# iptables -I INPUT -m tcp -p tcp --dport 2101 -j ACCEPT
# service iptables save
(or)
#iptables-save