ZyXEL Communications USG40 User Manual page 702

I cannot get Dynamic DNS to work.
• You must have a public WAN IP address to use Dynamic DNS.
• Make sure you recorded your DDNS account's user name, password, and domain name and have
entered them properly in the ZyWALL/USG.
• You may need to configure the DDNS entry's IP Address setting to Auto if the interface has a
dynamic IP address or there are one or more NAT routers between the ZyWALL/USG and the
DDNS server.
• The ZyWALL/USG may not determine the proper IP address if there is an HTTP proxy server
between the ZyWALL/USG and the DDNS server.
I cannot create a second HTTP redirect rule for an incoming interface.
You can configure up to one HTTP redirect rule for each (incoming) interface.
I cannot get the application patrol to manage SIP traffic.
Make sure you have the SIP ALG enabled.
I cannot get the application patrol to manage H.323 traffic.
Make sure you have the H.323 ALG enabled.
I cannot get the application patrol to manage FTP traffic.
Make sure you have the FTP ALG enabled.
The ZyWALL/USG keeps resetting the connection.
If an alternate gateway on the LAN has an IP address in the same subnet as the ZyWALL/USG's LAN
IP address, return traffic may not go through the ZyWALL/USG. This is called an asymmetrical or
"triangle" route. This causes the ZyWALL/USG to reset the connection, as the connection has not
been acknowledged.
Chapter 39 Troubleshooting
ZyWALL/USG Series User's Guide
702