CROESNET.EU

Because I use 1und1 as my ISP in Germany, I can also use their VOIP offering. I don’t think it is available for people who don’t have DSL provided by them.

Configuring a 1und1.de SIP trunk, and correctly register it, is a bit tricky. Where all the other provides I use can be configured completely via the trunk configuration menu-option, the 1und1 trunk requires a tweak in the config files to make a registration possible.

Using the 1und1 client website configurator, you can configure your normal landline number for VOIP usage, but need to be aware that in this case you can only make outbound calls. 1und1 can not transfer inbound calls on your Telecom number back into VOIP.
Using your landline number, just make it appear as caller-id on outbound calls. I use a fritzbox to transfer the incoming landline calls back into the trixbox.

Trunkname: 1und1

Peer details:

disallow=all
host=sip.1und1.de
username=49userid
fromuser=49userid
secret=passwd
type=friend
qualify=yes
nat=yes
insecure=very
fromdomain=1und1.de
canreinvite=no
allow=alaw&ulaw

Register String:

49userid:passwd@sip.1und1.de/49userid

To make registration work, it is necessary to add the following in your sip_general_custom.conf file, using the “config file editor” function:

localnet=192.168.0.0/255.255.0.0
externhost=yourhost.dyndns.com