FAQ
How to open a range of ports

Question:
I want to use my game on the PC behind Proxy+. The game FAQ says: You need to open a hole of ports XXXX-YYYY on the firewall to allow communication between game and the game server (another game user).

Answer:
Proxy+ is an application level proxy server. It is not a firewall. It means that you can't open a range of ports to be forwarded to/from the game server.

In some cases you can use Proxy+'s Mapped Links to connect the game to the server. These condition must be met:

• required range of ports must be small.
• the game must allow to change the remote server name or IP or the game must use DNS lookup to determine server's IP address. If the game uses hardwired IP address of the server it is not possible to use such game behind Proxy+.
• if the game or the server dynamically changes source or target port number the communication will not work probably.

1) If the game allows to change server host name or IP set it to IP address of PC with Proxy+. If there is no such option you have to determine what hostname asks the game when it does DNS name resolution (when it converts hostname to the IP address). This name can be found in game's documentation or FAQ. If the documentation doesn't mention server name you can use following method to determine server hostname:

• configure Proxy+ to start DNS Forwarder service (restart Proxy+ to activate new setting)
• configure PC with game to use Proxy+ as the DNS server (Network/TCP-IP properties)
• run the game and try to connect to the server. If all works fine you should find appropriate DNS request logged in Proxy+'s AccessLog.TXT file. Line with DNS request should contain server name. If there is no DNS request logged then the game probably doesn't use DNS to determine server address or there is another problem with TCP/IP settings.
  Note: use "Proxy Settings/Log Files/Display Logs" to see AccessLog content. Proxy+ doesn't write new lines immediately when the request appears. New line is written to the logfile memory cache (to achieve better performance) after the request is finished. The disc file is updated when the logfile cache is full (a few of tens of lines) or when the "Display Logs\AccessLog" WWW Admin page is requested.

2) Now you have to determine IP address associated with the hostname. Go the PC with Proxy+ , connect to the Internet and run following command (from DOS box window):

ping hostname

On the Windows NT systems you can use the command

nslookup hostname

In both cases you should get response with server's IP address.

3) Add IP address of the server and the hostname into HOSTS file on PC with the game. The TCP/IP system uses HOSTS file to convert server names to the IP addresses (if the hostname can't be found in this file the request is sent to the DNS server - if it is configured).

Each line of HOSTS file uses following format:

IP_ADDRESS HOST_NAME

Such that you have to add new line with the IP and hostname to the end of HOSTS file.

HOSTS file should be located in Windows directory on Win9x and in WinNT\System32\Drivers\Etc directory on Windows NT systems. There
is no HOSTS file by default. But in these directories you can find HOSTS.SAM (sample) file. Copy it using name HOST (no extension) and add new line as described above.

Note: if the PC with game use PC with Proxy+ as DNS server you can modify HOST file on the PC with Proxy+ instead of the file on PC with game.

4) Create Mapped Links and restart the Proxy+.

Related links:
Art04123 - The difference between the firewall and the application level proxy server