Tor server not seen

[jszymona <jszymona@xxxxx>]

I run tor server under Ubuntu 2.6.20-16

There are my   /etc/tor/torrc   settings:

SocksPort 9050 # what port to open for local application connections
SocksListenAddress 127.0.0.1 # accept connections only from localhost
Log notice file /var/log/tor/notices.log
Nickname xxx
ORPort 9001

There is a   /var/log/tor/notices.log   listing

Jul 17 12:26:44.017 [notice] Tor 0.1.2.14 opening new log file.
Jul 17 12:41:26.711 [warn] Your server (83.28.31.108:9001) has not
managed to confirm that its ORPort is reachable. Please check your
firewalls, ports, address, /etc/hosts file, etc.
[...]
Jul 17 14:08:22.871 [notice] Our IP Address has changed from
83.28.31.108 to 83.28.4.122; rebuilding descriptor.
Jul 17 14:09:33.115 [warn] eventdns: All nameservers have failed
Jul 17 14:09:33.150 [notice] eventdns: Nameserver 192.168.1.1 is back up
Jul 17 14:28:22.151 [warn] Your server (83.28.4.122:9001) has not
managed to confirm that its ORPort is reachable. Please check your
firewalls, ports, address, /etc/hosts file, etc.
[...]


What should I do to make my tor server be reachable?

JSz.