When connecting to a domain via SRV record, each host in the SRV record is being checked to see if it is in the same domain as the SRV entry.

Thus, if we have a SRV record that returns 3 hosts:

_mongodb._tcp.example.org -> host1.domain.com, host2.domai.com, host3.otherdomain.com

Mongo components return an error similar to: "Domain suffix from SRV record not matched input domain" or "Hostname host1.domain.com. is not within the domain example.org".

Code that causes this is here: https://github.com/mongodb/mongo/blob/master/src/mongo/client/mongo_uri.cpp#L428-L432

https://github.com/mongodb/mongo-tools/blob/master/common/connstring/connstring.go#L468-L488