Hi.
We have a small VoIP setup based on Ubuntu12 and the default shipped Asterisk 1.8.10.1~dfsg-1ubuntu1. We have a single upstream trunk and less than ten clients.
What we experience since some time is that clients often deregister and immediately register again. Most of the clients having problems are Siemens Gigaset handset. What we see in the asterisk debug is this:
-- Unregistered SIP '101'
-- Unregistered SIP '106'
-- Registered SIP '101' at 192.168.0.191:5060
-- Registered SIP '106' at 192.168.0.191:5060
> doing dnsmgr_lookup for 'voip.eutelia.it'
> doing dnsmgr_lookup for 'voip.eutelia.it'
-- Unregistered SIP '105'
-- Registered SIP '105' at 192.168.0.192:5060
-- Unregistered SIP '101'
-- Unregistered SIP '106'
> doing dnsmgr_lookup for 'voip.eutelia.it'
> doing dnsmgr_lookup for 'voip.eutelia.it'
-- Registered SIP '101' at 192.168.0.191:5060
-- Registered SIP '106' at 192.168.0.191:5060
This happens rather often, and if happens during a phone call the conversation is dropped 
I’ve read on some other forum those Gigaset doesn’t handle more than two SIP connections simultaneously (though allows to register more), so we’ve configured one or at most two extensions per base, but the disconnect still happens.
As said some other extensions configured either with Cisco or softphones won’t disconnect.
Is there a configuration issue maybe? Something I can change to have those handset better behave?
I tried to capture some traffic with tcpdump but I’m still unable to understand the deregistration reason.
sip.conf excerpt:
[104]
type=friend
secret=password
port=5060
nat=yes
host=dynamic
context=interno
canreinvite=no
qualify=yes
This is the SIP configuration of the Gigaset:
