How to set up connection manually?

In most cases DC++ should be able to automatically detect the appropriate connection method. This FAQ gives detailed information how to set up your incoming connection manually in case of the automatic detection fails or its result isn't acceptable for you.

Understanding DC++ connectivity

To make your life easier while using DC++ your connection must be set up correctly. In other words your incoming connection type must be correctly chosen for searches and downloads to work. The available connection modes depend on the structure of your network and the way you access the Internet. From a protocol perspective, there are two connection methods available: active mode and passive mode. While passive mode is almost guaranteed to work, it does not work as well as a properly configured active mode connection. For a more in-depth explanation, read Why do I need active mode?

Note that correct incoming connection settings are needed for searches and file downloads to work. These settings have no effect on ability to connecting to hubs or downloading hublists. This FAQ assumes that you are able to download hublists and connect to hubs as well as other peers can upload files from you. If this is not true then you must elminate another kind of problems before go on with this FAQ:

Decide what active mode setting to choose

It is very important to decide what active connection mode is available for you. It depends on your network structure, so you need to know exactly how you access the Internet. Is it a direct connection through a modem or do you have a local network and access the Internet through a router or other gateway? If unsure, this page should help you figure it out.

If you're still unsure what network devices you use to connect to the Internet, then use Google! It can give you information on every network device you own, just by searching for the model number printed on the device. Many ISPs call their device a simple modem when it is actually a router, so it never hurts to check.

In order to choose a proper active connection mode, you must know whether you are behind a router or gateway or if you access the Internet directly. You can also determine if you have a router or not by checking your external and internal IP addresses. If these IP addresses do NOT match then you access the Internet through a local gateway or router.

If you are still unsure you may want to consult your ISP support hotline or system administrator (if on an organization's network).

To manually configure your connectivity settings, uncheck Let DC++ determine the best connectivity settings in the Connectivity settings pane of the settings dialog. This will enable the controls on the Manual configuration pane where you can alter connectivity settings manually.

When you look at the Incoming connection settings you will find 2 options for active mode and the last option for being passive as a last resort. For being active:

Setting up active mode if you are directly connected (NOT behind a router)

Note hat this is the proper connection mode to choose if you're using DC++ to connect to local hubs and you plan to connect to users in your local network only.

Setting up active mode if you are behind a router

If you're behind a router (gateway) then your computer is a member of a separate local network so connections coming from the Internet must find their way into your computer that resides in a private network. For successful connectivity the router must be set up to open the communication ports DC++ uses and forward the incoming information from the Internet to the correct computer (the one that runs DC++). This is called port forwarding or port mapping and it requires configuration in the router device. There are ways to do port mapping automatically if your router supports one of the automatic port mapping protocols available in DC++. If none of the automatic port mapping ways are supported by the router, the configuration should be done manually to achieve a working active connection mode.

Automatic port mapping configuration

You can simplify the process of setting up port forwarding if your router supports automatic port mapping protocols such as NAT-PMP or UPnP. For more information, see What is NAT-PMP / UPnP?.

All broadband SOHO routers that manufactured in the recent years should support at least UPnP and it should be enabled by default (this may not always true for older models). In any case its best to consult the documentation of the device about what port mapping protocol does the router support and how to enable it.

Currently, DC++ includes support for both UPnP and NAT-PMP. If automatic port mapping is enabled in the connectivity configuration DC++ will try to map the ports with all the available mapper interfaces until a successful attempt. To enable automatic port mapping

Here are some tips if you can't make the automatic port mapping work and unable to figure out what's the problem:

Manual port mapping configuration

If you are unable to automate port forwarding with NAT-PMP or UPnP, you can follow the Manual port forwarding FAQ to achieve active connection mode. Note that manual port forwarding is an advanced task and it requires a minimal knowledge of computer networking.

Select passive mode as the last resort

If none of the above helped or you are not able to use active mode in your network (e.g. you have no access to the configuration page of the router/gateway or you have firewall service provided by your ISP) then you must choose Passive mode (last resort - has serious limitations) option in Connectivity Settings. As linked above, however, passive mode has several disadvantages.

If you still unable to search and/or download even in passive mode another possibility is that your ISP is blocking DC (and often other p2p protocols as well). This is also common at universities, at the workplace or other organizations, and is the topic of another FAQ.