Which error did you have? The Serious Network Trouble, or FRACK?
Well, we've created them from scratch (new servers) and are having these issues still. That said, the IPs Ive noticed in the logs that related to the serious network trouble errors are not trunk IPs, but endpoints. Could be both though, just haven't dug that deep to confirm/deny.
Here are our trunks, anveo, anveo 911, and then a FXO we have setup. Everything else are extensions:
ANVEO IN EXAMPLE
ANVEO OUT EXAMPLE