Running Compatibility Test and Fixing Common Problems
Compatibility Test will help you to find problems with configuration of your software and to see if your Internet connection allows to run A4Proxy. In order to run the test, first connect to the Internet and then select Compatibility Test from the Help menu.
Problems with IP address. A4Proxy requires that your computer should have a so-called public IP address, which is visible from the Internet. If your computer is connected via a modem, it is usually given such an address each time you go on-line; however, in some network configurations public IP addresses are not assigned. In this case A4Proxy will not be able to check proxies for anonymity. Look at the lines starting with Host address: if there isn’t any line saying “Public IP”, you will have to talk with your provider or network administrator to find out if you can get a public IP for your machine.
It is usually a problem when there is a router between your computer and the Internet. Since your computer doesn’t contact the outside world directly, it hasn’t got a public IP. However, A4Proxy needs the public IP address of your Internet connection in order to test proxy servers for anonymity: it compares the IP address as it is shown by the proxy servers to the sites, with the true IP address of your connection. If your true IP is not revealed, the proxy is considered anonymous.
In some cases, the public IP is there, but A4Proxy fails to recognize it. In this case you can enter the IP manually: select Special Options in the Options menu in A4Proxy, enable the Use Fixed Public IP Address option and enter your IP in the field.
See also: Router between you and the Internet
See also: Public vs Private IP addresses – what does it all mean? by William McLachlan
Problems with ports. A4Proxy requires that the port numbers selected in the Browser Port and Check Port options on the Proxy Options tab should be available to A4Proxy to use. The default (and recommended) value for both of these settings is 80 and you should not change it unless you see errors in your Compatibility Test results on this port. However, if you do see errors associated with the port(s) selected in the options above, you must change the port numbers so that there will be no errors on the ports chosen. The Browser Port is used for communication with your web browser and must always be the same as the one entered in your browser together with address 127.0.0.1. If you change the Browser Port setting in A4Proxy, you must change the port in the browser settings as well. If the port selected in the Browser Port setting is occupied by other software (that will be indicated by the errors in the compatibility test results), you will be unable to browse the web until you change the setting to a free port.
The Check Port is used for checking proxies. If the port selected in this option is occupied by other software (which may be indicated by the errors in the compatibility test results), you will not receive any valid results of proxy checking: all proxies will be reported as non-working. In this case you should change the port number to some other value.
Errors reported for port 21 or 443 of your public IP indicate that some other software installed on your computer interferes with A4Proxy and as the result you cannot check proxy servers for support of FTP and HTTPS protocols respectively (but you can still check proxies for anonymity and speed).