I have a domain setup with mixed systems. It's running Win2k16 server. Some clients are Windows and some are Linux. Most Linux clients are Ubuntu servers, in this case an 18.04. The Ubuntu 16s I have setup with an older winbind join are functioning fine, but I found it wouldn't work on 18 properly on the most recent server that was spun up. The domain is local only, not open to the internet, and I've trying to use this guide link found here, to use sssd to bind to the domain. When it tries to resolve with a realm -v command or a realm join command, it attempts to perform an LDAP lookup, including an _ldap._tcp.mydomain.com (replaced with my domain of course), which is not DNS'd, and "Performing LDAP DSE Lookup on: xxx.xxx.xxx.xxx" where an unknown external IP shows up there. And of course it times out, so it fails to join the domain.
My question is, where is this IP coming from, and how can I correct this? The domain is reachable from the host without issue otherwise. This is quite frustrating. Thanks.
