My QuickVPN connection is having problems connecting. What can I do to troubleshoot the problem?

This article describes how to troubleshoot QuickVPN connections.
Router FirmwareThe following table lists compatible QuickVPN routers and the recommended minimum firmware version that should be used for stable QuickVPN connectivity. Visit http://www.linksys.com/download to download the latest firmware version for your router.
Router
Firmware Version
WRV54G
2.37 or higher
RV042
1.3.6 or higher
RV016
2.0.1 or higher
RV082
1.1.6.3 or higher
Router IP Address ConflictsThe router being used to serve QuickVPN connections should not be assigned the default 192.168.1.1 IP address. If a remote client is trying to connect behind a router that is also using 192.168.1.1, the QuickVPN connection will fail. NOTE: The router will automatically attempt to change its default IP address when the first QuickVPN user account is added.Router SettingsThese settings, which can be found in the web-based Setup utility of your router, should be configured to allow QuickVPN connections.
Host Name:
Domain Name: Should be filled in with any domain name followed by .com, .net, .org, etc. (for example, mylinksys3.com). The domain does not have to be a valid domain that exists on the Internet. Without a domain name, you may get an "ERROR: malformed status line -1" entry in the wget_error.txt log file (found in the \Program Files\Linksys\Linksys VPN Client folder)
MTU: An MTU value of 1428 can be used and decremented further to test.
HTTPS (RV-series VPN routers only): Should be set to Enable.
Port Forwarding: Ports 443 and 500 should not be forwarded to the LAN. These well-known ports are used to create the secure IPSec tunnels used by QuickVPN.
DMZ: DMZ (De-Militarized Zone) features should not be used.
QuickVPN Client user accounts: QuickVPN Client user accounts need to be set (checked P) to Active.
The following table shows the web-based Setup utility tab & sub-tab locations of the settings mentioned above.
Setting
WRV54G
RV-Series
Host Name
Setup -> Basic Setup
Setup -> Network
Domain Name
Setup -> Basic Setup
Setup -> Network
MTU
Setup -> Basic Setup
Firewall -> General
HTTPS
n/a
Firewall -> General
Port Forwarding
Applications & Gaming ->Port Range Forwarding
Setup -> Forwarding
DMZ
Applications & Gaming ->DMZ
Setup -> DMZ Host
QuickVPNClients Accounts
Access Restrictions ->VPN Client Access
VPN -> VPN Client AccessOther IPSec VPN Client SoftwareLinksys QuickVPN will not function correctly with other IPSec software installed on remote client computers. To successfully connect and avoid conflicts, all other IPSec client software must be completely uninstalled and QuickVPN should be the only IPSec software used.