Hi, I just tried to build using http://dl.fedoraproject.org/pub/epel/6/SRPMS/pdns-3.1-2.el6.src.rpm on CentOS 6.4 final (kernel: 2.6.32-358.2.1.el6.x86_64), but it failed when looking for ldap libs: Note: I did not change anything in the original spec file. ... + ./configure --build=x86_64-redhat-linux-gnu --host=x86_64-redhat-linux-gnu --target=x86_64-redhat-linux-gnu --program-prefix= --prefix=/usr --exec-prefix=/usr --bindir=/usr/bin --sbindir=/usr/sbin --sysconfdir=/etc --datadir=/usr/share --includedir=/usr/include --libdir=/usr/lib64 --libexecdir=/usr/libexec --localstatedir=/var --sharedstatedir=/var/lib --mandir=/usr/share/man --infodir=/usr/share/info --sysconfdir=/etc/pdns --libdir=/usr/lib64/pdns --disable-static --with-modules= --with-lua '--with-dynmodules= gmysql gpgsql pipe geo ldap gsqlite3' --enable-cryptopp ... checking for ldap_set_option in -lldap_r... no checking for ldap_set_option in -lldap... no configure: error: ldap library (libldap) not found However, libldap exists at the required place (/usr/lib64): $ ls -la /usr/lib64/ | grep ldap drwxr-xr-x. 4 root root 4096 Mar 11 16:06 evolution-openldap lrwxrwxrwx. 1 root root 10 Sep 21 2012 libldap-2.4.so.2 -> libldap.so -rw-r--r-- 1 root root 781914 Mar 20 15:57 libldapbackend.a -rwxr-xr-x 1 root root 1151 Mar 20 15:57 libldapbackend.la -rwxr-xr-x 1 root root 379419 Mar 20 15:57 libldapbackend.so lrwxrwxrwx. 1 root root 12 Sep 21 2012 libldap_r-2.4.so.2 -> libldap_r.so lrwxrwxrwx 1 root root 29 Mar 11 16:06 libldap_r.so -> /lib64/libldap_r-2.4.so.2.5.6 lrwxrwxrwx 1 root root 27 Mar 11 16:06 libldap.so -> /lib64/libldap-2.4.so.2.5.6 -rwxr-xr-x 1 root root 40320 Feb 22 09:49 libsmbldap.so.0 Here is the relevant part from config.log: ... configure:17992: checking for ldap_set_option in -lldap_r configure:18017: g++ -o conftest -D_GNU_SOURCE -O2 -g -pipe -Wall -Wp,-D_FORTIFY_SOURCE=2 -fexceptions -fstack-protector --param=ssp-buffer-size=4 -m64 -mtune=generic -DLDAP_DEPRECATED -O2 -g -pipe -Wall -Wp,-D_FORTIFY_SOURCE=2 -fexceptions -fstack-protector --param=ssp-buffer-size=4 -m64 -mtune=generic conftest.cpp -lldap_r -lz >&5 /usr/lib/gcc/x86_64-redhat-linux/4.4.7/../../../../lib64/libldap_r.so: undefined reference to `ber_sockbuf_io_udp' collect2: ld returned 1 exit status ... configure:18033: checking for ldap_set_option in -lldap configure:18058: g++ -o conftest -D_GNU_SOURCE -O2 -g -pipe -Wall -Wp,-D_FORTIFY_SOURCE=2 -fexceptions -fstack-protector --param=ssp-buffer-size=4 -m64 -mtune=generic -DLDAP_DEPRECATED -O2 -g -pipe -Wall -Wp,-D_FORTIFY_SOURCE=2 -fexceptions -fstack-protector --param=ssp-buffer-size=4 -m64 -mtune=generic conftest.cpp -lldap -lz >&5 /usr/lib/gcc/x86_64-redhat-linux/4.4.7/../../../../lib64/libldap.so: undefined reference to `ber_sockbuf_io_udp' collect2: ld returned 1 exit status .... Am I doing something wrong? Why it can't find the ldap libraries? Please advise. Thanks, Nick