Not sure how to explain this, but I have a highly modified extensions.conf, so this detail made quite a impact. I am running Asterisk 13.1.0 and its been in use for a half a year or so with no issues (upgraded from a earlier release). It has DAHDI PRI and SIP trunks to it. In the SIP.conf file I have the SIP provider host defined as a dns like what was specified by the hosting company when I put this in several years ago. (i.e. host=sip.host.co) and it has been working fine for years. We had a power outage and all of a sudden nothing would work correctly. If found the SIP calls where going to the general context instead of the specified context, and the channels where being defined as SIP/xxx.xxx.xxx.xxx as the IP of the hosting company instead of the context name like before. I finally changed the host definition to host=XXX.XXX.XXX.XXX instead of the dns name and everything started to work. I thought the dns was not working but I did a ping and it came up as the correct IP address. Any idea why all of a sudden this was a issue? Thanks!
What do you mean by highly modified? All extensions.conf should start from an empty file… It suggests to me that you may be using a GUI, in which case you need to contact the GUI people.