Hi,
Thanks for the suggestion. I cannot find the 'host' option when I view an Extension in FreePBX panel. After some further searching it seems to be pointing to a setting called 'fromdomain' in sip.conf. I have added fromdomain=sip.domain.com to sip.conf and that does not seem to have any effect. It could be that I'm using pjsip? For example, I call 6004 from 6002 and the following shows as the incoming call '6002@10.0.5.174'. I need it to show '6004@sip.domain.com'