Thank you for your answer: I use a DSL-Router (fritz.box 7113). VoIP-devices directly connected to the Router work fine. On my notebook (conneted via wLan) I use a SIP-software, provided by "1&1", which is working fine, too.
The problem appears when I call from the 6300i to a fixed or a mobile device. The phone is working fine when I use it as a cell-phone.
Does this help?
Christian


So it doesn't seem to be a WLAN- oder Firewall-problem.




