This post is about the inability to log in to the forums. The symptoms, cause, technical details and a proposed workaround solution are described. If you are unable to log in to the forums and your symptoms match the description, try the suggested Solution. If you are not interested in the technical details, feel free to skip them.
The forum login/authentication system is not compatible with HTTP-only web proxies (those that proxy HTTP traffic but not HTTPS), preventing successful login. In particular, it is not compatible with transparent proxies utilised by many major ISPs. For example, many players who use the UK ISP called NTL have problems logging in to the forums or are completely unable to log in.
The issue arises when a users's HTTP traffic is passed through a proxy but his HTTPS traffic isn't, a common scenario with ISPs that use transparent proxies. However, transparent proxies are not the only possible cause, the issue can also arise with certain configurations of proxy settings in the user's web-browser. (More technical details below)
The solution (described in detail below) is to configure the user's browser to pass both HTTP and HTTPS traffic through the same proxy server.
Technical details
The symptom of the issue is this. You go to one of the forums, e.g. English General. You type in your username and password correctly in the login box at the top right, and try to log in. If this is the first time you are trying to log in, then a page with your characters is supposed to come up, but instead you just receive the page with no characters in the list. If you have successfully logged in before and therefore have selected a character, then instead you just simply get bounced back to the same forum. No error message comes up and you are apparently not logged in. Instead of showing your selected character in the top right corner, the same empty log in box is displayed. No matter how many times you try, you don't log in.
The cause of the issue is this. The forum login system uses a mixture of URLs, some of which use HTTP, some of which use HTTPS. The forum pages themselves use HTTP, but when you click Log In, you are first taken through an HTTPS URL (which performs the authentication) and then you are redirected back to the HTTP forum page. The problem happens because of this mixing of HTTP and HTTPS protocols.
If your web traffic is proxied such that your HTTP traffic goes through a proxy, but your HTTPS traffic doesn't, then the source IP address from which you are apparently making the connections to the URLs in question are different for the two protocols. When accessing an HTTP URL, your apparent source IP (that the forum server sees) is that of your proxy server, but when accessing an HTTPS URL, the source IP is that of your computer. The login system used by these forums seems to check for source IP address and therefore if the HTTP and HTTPS traffic comes from different addresses then you can't succesfully log in.
This problem can arise in several situations. Here are the two most common scenarios I have encountered:
ISPs that use so called "transparent" proxies. Example: NTL (2nd largest ISP in UK). Even if the user has no proxy server specified in their web-browser, nevertheless these ISPs forcefully pass web-traffic through their proxy servers. Unfortunately, this is usually done only to HTTP traffic and not to HTTPS. The result is that, unknown to the user, their HTTP traffic goes via the ISPs proxy servers, and therefore has a different source IP address than the user's IP address.
User's whose proxy settings in their browser is configured such as to pass HTTP traffic through a proxy server but not HTTPS traffic. This can even happen without the user's knowledge, for example when automatic proxy configuration settings are used. Many institutions that provide automatic proxy settings provide them such that only HTTP traffic is proxied. Example: several major UK Universities.
Solution
The solution in all cases involves manually setting up appropriate proxy server settings in your web-browser. I am going to describe in detail the necessary steps.
First, you need to determine whether your web-traffic is indeed currently going through a proxy server or not, and if so, what is its name. If it's not, then your problem with logging in is probably caused by something else and this post does not apply to you. To check this, visit this page:
What Is My IP Address? - Dedicated to IP address discussion
If you are going through a proxy server, you will see a repot like this:
Proxy Server Detected!
Proxy Server IP address: W.X.Y.Z
Proxy Server Details: name.of.proxy.server
Proxy Reports IP as: A.B.C.D
At this point, make a note of the name of the proxy server (indicated in bold in the example above), as you will need it. Next you have to configure your web-browser such that all traffic (both HTTP and HTTPS) goes through the same proxy server. The steps for this are different for each browser, the exact steps are explained here for Internet Explorer 6.
1) In Internet Explorer, go to Tools->Internet Options->Connections tab.
2) Click "LAN Settings" button on the middle right. A new dialog box should open.
3) Uncheck the "Automatically detect proxy settings" setting if it's checked.
4) Under Proxy Server, check the "Use a proxy server for your LAN" setting.
5) In the Address box, type in the name of the proxy server you found above (the bold part). In the Port box, type 8080.
6) Click the Advanced button. In the new dialog box, make sure the "Use the same proxy server for all protocols" setting is checked.
7) Hit OK sufficient number of times.
If the above doesn't work for you, you can also try with Port number 80 instead of 8080, which may work for some people. For other web browsers, you need to make the equivalent settings, i.e. specify a proxy server manually and make sure both HTTP and HTTPS traffic go through the same one.
Conclusion
This issue is a pain. I have made this post during the forum beta test as well, as many people were unable to log in to the beta forums. The solution suggested in this post allowed most people with this problem to successfully log in.
Unfortunately this is not 100% Blizzard's fault so we can't just blame Blizzard for it. It's due to the interaction between the forum software and the user's or their IPSs proxy configuration. This is not an uncommon problem actually, I have encountered many forums, web-sites and web services that suffer from the same problem. It arises any time the web server checks the source IP address for security purposes.
