I'll start with I'm not an AIX expert, I inherited a lot of AIX servers to maintain.
My problem is on AIX 7.1 TL4 SP4 environments. I'm running named as a DNS forwarder only to internal DNS servers.
These AIX servers have a customized UDP ephemeral port range to avoid conflicting with the primary application running on them that defaults to a portion of the typical ephemeral range.
Since configuring named, I've seen that named is ignoring the OS configured ephemeral range.
The OS restricted UDP range is: 32768 to 49999.
I've seen requests from named using source ports above 49999.
After googling, the only article I can find that references named/bind and ephemeral ports is a page from ISC related to BIND 9. There's a setting "use-v4-udp-ports { range 1024 65535; };" that forces named to use a fixed UDP range for source ports. But the IBM documentation on named doesn't cover this option.
I tried putting the setting onto named.conf on a test system but now named won't start and no errors are logged.