FAQ/How to solve problems with outgoing calls in firmware version 8?

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Answer

Since firmware version 8 the phone is sending additional information in the SIP header which can cause SIP packets to exceed the maximum size of an IP packet that can be transmitted without fragmentation. Some routers or DSL lines cannot handle such large packets which causes the call to fail.

Depending on the MTU size your network components can process, in some cases large packets are required to be fragmented.


This can be achieved by enabling an internal setting named ip_frag_enable (which is disabled by default)

Use either provisioning or HTTP GET requests in order to enable this setting.

For the latter you would need to enter the following URL in a browser

http://phoneIP/dummy.htm?settings=save&ip_frag_enable=on

Note: If you have set up user name and password to protect the webinterface, Hidden tags need to be disabled in order to have the setting change taking effect.

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