Ok, ldd against rlm_ldap.so gives
rlm_ldap.so: ... libgnutls.so.26 => /usr/lib/x86_64-linux-gnu/libgnutls.so.26 (0x00007f7e47947000) ..
Ugh. I wouldn't be surprised if that was it.
Looks like I have to rebuild my freeradius-ldap too to use openssl right? The RedHat documentation on the freeradius site doesn't say anything about how to switch to openssl. Are there any pointers how to do this?
There is no accounting for taste, but there are numerous posts on numerous lists advising against GnuTLS, even OpenLDAP guys do not recommend RedHat packages at all. It is always reminded here on this list that we should read, and read and read as much as we can. Far from 'endorsing' any technology, try to switch to OpenSSL. There are plenty of tutorials online about how to do that. Good luck.