My ISP uses a transparent proxy, what should I do?
Caveat: This is a large and complex topic. It is not possible to cover all variations here.
Short reply: change to an ISP that does not force a proxy upon you. If you cannot or do not want to then read on.
What is a proxy?
Basically a middleman. When you are browsing a site through a proxy your requests are sent to the proxy and the proxy forwards them to the site instead of you connecting directly to the site. There are several classifications (the terminology is far from standard):
| Transparent | A transparent proxy is one that needs no configuration on the clients. It works by automatically redirecting all port 80 traffic to the proxy. (Sometimes used as synonymous for non-anonymous.) |
|---|---|
| Explicit/Voluntary | Clients must configure their browsers to use them. |
| Anonymous | The proxy sends no client identification to the server. (HTTP_X_FORWARDED_FOR header is not sent; the server does not see your IP.) |
| Highly Anonymous | The proxy sends no client nor proxy identification to the server. (HTTP_X_FORWARDED_FOR, HTTP_VIA and HTTP_PROXY_CONNECTION headers are not sent; the server doesn't see your IP and doesn't even know you're using a proxy.) |
| Public | (Self explanatory) |
A transparent proxy may or may not be anonymous, and there are several levels of anonymity.
How do I find out if I'm behind a (transparent/anonymous) proxy?
Try ProxyJudge. It lists the HTTP headers that the server where it is running received from you. The relevant ones are HTTP_CLIENT_IP, HTTP_X_FORWARDED_FOR and REMOTE_ADDR.
Why am I listed as not connectable even though I'm not NAT/Firewalled?
The tracker is quite smart at finding your real IP, but it does need the proxy to send the HTTP header HTTP_X_FORWARDED_FOR. If your ISP's proxy does not then what happens is that the tracker will interpret the proxy's IP address as the client's IP address. So when you login and the tracker tries to connect to your client to see if you are NAT/firewalled it will actually try to connect to the proxy on the port your client reports to be using for incoming connections. Naturally the proxy will not be listening on that port, the connection will fail and the tracker will think you are NAT/firewalled.
Can I bypass my ISP's proxy?
If your ISP only allows HTTP traffic through port 80 or blocks the usual proxy ports then you would need to use something like socks and that is outside the scope of this FAQ.
The site accepts connections on port 81 besides the usual 80, and using them may be enough to fool some proxies. So the first thing to try should be connecting to http://cinemageddon.org:81. Note that even if this works your bt client will still try to connect to port 80 unless you edit the announce url in the .torrent file.
Otherwise you may try the following:
- Choose any public non-anonymous proxy that does not use port 80 (e.g. from this, this or this list).
- Configure your computer to use that proxy. For Windows XP, do Start, Control Panel, Internet Options, Connections, LAN Settings, Use a Proxy server, Advanced and type in the IP and port of your chosen proxy. Or from Internet Explorer use Tools, Internet Options, …
- (Facultative) Visit ProxyJudge. If you see an HTTP_X_FORWARDED_FOR in the list followed by your IP then everything should be ok, otherwise choose another proxy and try again.
- Visit CG. Hopefully the tracker will now pickup your real IP (check your profile to make sure).
Notice that now you will be doing all your browsing through a public proxy, which are typically quite slow. Communications between peers do not use port 80 so their speed will not be affected by this, and should be better than when you were “unconnectable”.
How do I make my bittorrent client use a proxy?
Just configure Windows XP as above. When you configure a proxy for Internet Explorer you're actually configuring a proxy for all HTTP traffic (thank Microsoft and their “IE as part of the OS policy” ). On the other hand if you use another browser (Opera/Mozilla/Firefox) and configure a proxy there you'll be configuring a proxy just for that browser. We don't know of any BT client that allows a proxy to be specified explicitly.
Why can't I signup from behind a proxy?
It is our policy not to allow new accounts to be opened from behind a proxy.
Does this apply to other torrent sites?
This section was written for TorrentBits, a closed, port 80-81 tracker which CG is based upon. Other trackers may be open or closed, and many listen on e.g. ports 6868 or 6969. The above does not necessarily apply to other trackers.
Why can't I connect? Is the site blocking me?
Your failure to connect may be due to several reasons.
Maybe my address is blacklisted?
The site blocks addresses listed in the (former) PeerGuardian database, as well as addresses of banned users. This works at Apache/PHP level, it's just a script that blocks logins from those addresses. It should not stop you from reaching the site. In particular it does not block lower level protocols, you should be able to ping/traceroute the server even if your address is blacklisted. If you cannot then the reason for the problem lies elsewhere.
If somehow your address is indeed blocked in the PG database do not contact us about it, it is not our policy to open ad hoc exceptions. You should clear your IP with the database maintainers instead.
Your ISP blocks the site's address
(In first place, it's unlikely your ISP is doing so. DNS name resolution and/or network problems are the usual culprits.) There's nothing we can do. You should contact your ISP (or get a new one). Note that you can still visit the site via a proxy, follow the instructions in the relevant section. In this case it doesn't matter if the proxy is anonymous or not, or which port it listens to.
Notice that you will always be listed as an “unconnectable” client because the tracker will be unable to check that you're capable of accepting incoming connections.
