Yeah, I opened a ticket with info from this post and they said that it would not work.
Their reply was:
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In this case unfortunately isn't a possibility due to how our system works by
assigning a DID a specific server (IP) and for incoming calls to work you would
need to have the same server (IP) registered in your phone than the one assigned
with the DID. Such an example is, you have a DID with (Chicago4) you would need
to use (Chicago4) on the phone registration for incoming calls to work, let's
say your phone switches to Chicago 5,6,7,8 the incoming calls won't work since
doesn't match the one assigned on the customer portal on our end. At most may
work only with outbound calls.
Based on your behavior seems like a NAT resolution issue or a time out in the
connection, we may advise you disable SIP ALG if it's enabled on your network or
attempt a firmware update on the Obi Hai to check if may solve the issue.
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Well, I know about the SIP ALG and never have that enabled. So I wonder if an NAT issue? Perhaps rather than an alternate server the retry timer on the phones needs adjustment? I say that because my neighbor said her phone showed her server was offline (it may have gone down for a while or she may have had issues getting through the internet to it). In any event, the server was up and when she did a power cycle, it came up. The phone had been offline 3 days but the server was up and working. This kinda seems like there is a retry timer I should adjust. I'm using default
VOIP.MS settings. I see on my own phones that sometimes a connection goes down and comes back up, so I know the phone has retried. But does it finally throw up its hands and give up until I powercycle?