Problematic routers and modems.

Always update your broadband router firmware. Visit the manufacturer website Support or Download section.

This thread is a work in progress based on internet information and our own QA staff. Some of the recommended fixes might not be possible on your router.

Internet access issues:

1) Due to too many connections:
Broadband routers performing NAT (Network Address Translation) have a table in memory that maps your private network TCP and UDP sessions to your public IP address. The router NAT table is limited in size, sometimes as small as 4096 sessions. When the NAT table is full, poorly designed or cheap routers simply crash and reboot. Other routers will ignore new outbound UDP sessions (ex: voice chat, file transfers) and/or reset (RST) new TCP outbound connections (ex: web browsing). To the user, the UDP ignore and TCP resets appear to be ISP traffic throttling, when the problem is in fact the user's saturated broadband router.

The following routers have known problems with too many global connections. Limiting them to 200 or less should fix the problems. Since global connections aren't adjustable in Xfire, update the router firmware:
* Ale 130 - USB ADSL modem
* D-Link 302G
* D-Link 5xx
* D-Link 6xx
* D-Link DI-624
* D-Link DSL-G664T
* Linksys BEFSR41/BESR41v3/BEFSR41v4
* Linksys Wireless-b
* Linksys WRT54G/WRT54GL/WRT54GS/WRT54Gv5
* Netgear DG632
* Netgear DG834G
* Netgear MR814
* Netgear Rangemax 802.11n WPN824
* Netgear WGR614 v5
* Netgear WGT524
* SMC Barricade 7004 BR
* SpeedStream 5100(a) ADSL bridge - updating the firmware should fix the problem http://subscriber.communications.siemens.com/subscriber_networks/upg-firmware.shtml
* SpeedStream 5100b ADSL modem - updating the firmware should fix the problem http://subscriber.communications.siemens.com/subscriber_networks/upg-firmware.shtml
* SpeedStream 5660 in Router/NAPT configuration. Latest firmware is 2.(3).7. Alternate workarounds:
---- Switch to bridged mode. (For security, firewall your network.)
---- When it dies, just power-cycle the router and continue on.
* Westell 6100
* W-Linx MB401-S
* ZTE ZXDSL 831

2) Due to Universal Plug and Play (UPnP). Update the firmware. If problems persist, disable UPnP on the router:
* D-Link 5xx
* D-Link 6xx (can also be caused by too many connections)
* D-Link DI-604 (one case of random disconnects with UPnP enabled in Azureus)
* Dynalink RTA1025W
* Some SpeedStreams
* TP-LINK TL-R410
* ZyXEL Prestige 660H(W) (Firmware versions PE8+ will fix this)

3) Due to Port Forwarding:
* D-Link DI-514 (not port forwarding UDP protocol consistently)

4) PPPoE MTU too large
If the person's ISP uses PPPoE or PPPoA, then one cause of disconnects can be their MTU value.
This site or this one can help you figure out your proper MTU value: http://www.dslreports.com/faq/6266
Here is what Microsoft has to say about MTU: http://support.microsoft.com/default.aspx?scid=kb;en-us;283165

ex: Dlink DI-524 was using 1492 MTU for PPPoE connection.

5) Reason not yet verified:
* Apple airport extreme (802.11g wireless with wep 128bit)

6) Others
* (D-link routers, any other router with game mode or DMZ enabled) - If you look at the console or other debugging info, you may find a piece of data is detected as bad by the integrity checking function ("hash failure"). This is most likely caused by a bad router that is consistently mangling a specific piece-data packet.
Some routers employ a trick called game mode, rewriting internal and external IP address bytes within incoming and outgoing packets. This allows older games that hard-code IP addresses to function behind a NAT setup. However, when such an address-byte sequence is coincidentally present within a packet being sent, the router mistakenly rewrites the data. This changes the content of the packet, which fails hash-checking. Any incoming packet that has a byte sequence that happens to match the address byte sequence is susceptible to mangling, an event estimated to happen once for about every 4GB of data transferred. Xfire v1.59 handles the CRC failures by changing encoding method and resending data.
* D-Link DI 604 (one case of speeds decreasing)
* XAVI X8222r (Corrupts DNS cache - Fixed by Putting the modem/router into bridge mode)

7) Some solutions:
* Updating the router firmware
* Turning off the UPnP (in the Xfire client and in the router) and doing manual port forwarding
* Restricting the number of global connections to something between 60 and 100
* Turning off DHT
* Putting the modem/router into bridge or gateway mode (doesn't apply to modems that aren't routers)
* Getting a new router or modem (D-link Gaming Router is recommended)