The Blizzard Downloader is a high-speed, distributed downloading application that operates on a peer-to-peer protocol - that is, everyone who downloads the files also help send the file to others. By its very nature, this technology is dependant on your computer's ability to make connections and communicate effectively with other computers. Many users share their Internet connection using a router or have a software firewall installed on their machine that must be configured to allow for proper use of the downloader.
If you are having issues with the downloader, please visit our Blizzard Downloader Troubleshooting page.
Routers
A router is a physical device that allows you to share your internet connection between multiple computers. Most routers will not allow incoming traffic to your computer unless you have configured them to forward the necessary TCP ports to your computer. The Blizzard Downloader requires that TCP ports 3724 and 6112 be forwarded. It can also benefit from having ports 6881 through 6999 forwarded.
Third-party assistance on configuring other popular routers can be found at Portforward.com (note: this site is not affiliated nor supported by Blizzard Entertainment). Many manufacturers also offer guides on their websites, in the included documentation, or on the installation CD.
Note: On most routers, you can find the brand and model number on or near the serial number sticker on the bottom of the device.
Firewalls
A software firewall is an application installed on the computer or provided by the Operating System that actively blocks communication between the computer and the internet. The Blizzard Downloader requires that ports 3724 and 6112 be open. It can also benefit from having ports 6881 through 6999 open. Head to the Blizzard Downloader Firewall Guides page for step-by-step instructions on configuring some popular firewall software packages. You may also be able to find information on how to open ports on your firewall company's website, in the included documentation, or on the installation CD.
Downloading to Multiple Computers on your Network
If you have multiple computers on your network and would like to get files using the Blizzard Downloader to each computer, we recommend that you configure one computer to use the downloader effectively by forwarding the necessary ports on your router as necessary. Once that computer has completed the download, you can use normal file or folder sharing to transfer the file(s) from that computer to the other computers on the network just as you would any other file. The file(s) downloaded can usually be found in the directory you installed the game to on your hard drive, unless the Blizzard Downloader prompted you for a directory in which to save the file(s).
Depending on your network setup, attempting to use the Downloader from multiple computers on the same network may cause them to split the available internet bandwidth to download the same files - slowing each computer's download significantly. Downloading to one computer and then simply sharing the file on your network can speed up the download by focusing all available bandwidth on one download.
If you have problems transferring files over your network or are unsure how to complete this task, please contact whoever set up your network, your computer manufacturer, or a qualified network specialist for further assistance. Blizzard Entertainment can not offer assistance in setting up your home network.
Network Card Known Issues
In our testing of the Blizzard Downloader, we found that some network cards have issues with the large number of connections necessary for proper Blizzard Downloader operation. If this seems to be the case, you may need to update to the latest drivers. We recommend you visit the manufacturer's homepage for the latest drivers.
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