ZyXEL Communications P-2302R Series User Manual

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P-2302R Series User’s Guide
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Chapter 37 Troubleshooting
37.8  Problems with Voice Service
37.9  Pop-up Windows, JavaScripts and Java Permissions 
In order to use the web configurator you need to allow:
• Web browser pop-up windows from your device.
• JavaScripts (enabled by default).
• Java permissions (enabled by default).
Note: Internet Explorer 6 screens are used here. Screens for other Internet Explorer 
versions may vary.
37.9.1  Internet Explorer Pop-up Blockers
You may have to disable pop-up blocking to log into your device. 
Either disable pop-up blocking (enabled by default in Windows XP SP (Service Pack) 2) or 
allow pop-up blocking and create an exception for your device’s IP address.
37.9.1.1  Disable Pop-up Blockers
In Internet Explorer, select ToolsPop-up Blocker and then select Turn Off Pop-up 
Blocker
Table 138   Troubleshooting Voice Service
PROBLEM
CORRECTIVE ACTION
After VoIP is 
configured and 
working, others are 
unable to call you 
or you lose your 
connection during a 
call. There is a NAT 
router between the 
Prestige and the 
SIP server. 
This could be caused by a short NAT UDP session timeout on the NAT router. 
When the SIP session’s entry in the NAT table times out, the NAT router does not 
have any record to use for forwarding VoIP traffic to the Prestige.
If possible, set the NAT router to use a longer NAT UDP session timeout.
Otherwise, try one of the following:
Shorten the registration expiration period (see the Expiration Duration field 
in the VoIP Advanced screen) in order to cause the Prestige to re-register 
with the SIP register server more frequently. Note that this will not help if the 
SIP register server enforces a long registration expiration period (since the 
Prestige will also use the period set by the SIP register server).
Use STUN. If your VoIP service provider does not have a STUN server, you 
can still enable STUN and enter the IP address and port number of the SIP 
server in the STUN server fields. This causes the Prestige to send STUN 
requests to the SIP server. While this will not make STUN work (since there 
won’t be any responses to the STUN requests), it should keep the NAT UDP 
session in the NAT router.