You can switch DirectAdmin to use SSL instead of plain text. -> https instead of http on port 2222.
Note that this is for the DirectAdmin connection on port 2222, *not* for apache.
If you’re tryting to setup a certificate for your domain through apache, use this guide.
If you do not have your own certificates, you’ll need to create your own:

/usr/bin/openssl req -x509 -newkey rsa:1024 -keyout /usr/local/directadmin/conf/cakey.pem -out /usr/local/directadmin/conf/cacert.pem -days 9999 -nodes

chown diradmin:diradmin /usr/local/directadmin/conf/cakey.pem
chmod 400 /usr/local/directadmin/conf/cakey.pem

---

This is the old method, use either the one above, or this one. The end result is the same, but takes more steps.

openssl req -new -x509 -keyout /usr/local/directadmin/conf/cakey.pem.tmp -out /usr/local/directadmin/conf/cacert.pem -days 3653

openssl rsa -in /usr/local/directadmin/conf/cakey.pem.tmp -out /usr/local/directadmin/conf/cakey.pem

rm -f /usr/local/directadmin/conf/cakey.pem.tmp
chown diradmin:diradmin /usr/local/directadmin/conf/cakey.pem
chmod 400 /usr/local/directadmin/conf/cakey.pem

(Paste these one at a time as the first 2 require user input)

---

If you already have your own certificate and key, then paste them into the following files:
certificate: /usr/local/directadmin/conf/cacert.pem
key: /usr/local/directadmin/conf/cakey.pem
Edit the /usr/local/directadmin/conf/directadmin.conf and set SSL=1 (default is 0). This tells DA to load the certificate and key and to use an SSL connection. DirectAdmin needs to be restarted after this change.
If you also have a CA Root Certificate, this can be specified by adding:
carootcert=/usr/local/directadmin/conf/carootcert.pem
into the /usr/local/directadmin/conf/directadmin.conf file (won’t exist by default) and by pasting the contents of the caroot cert into that file.
Note, as of 1.30.2, you can set the value of the SSL redirect should a User connect to an https connection with plaintext http.
http://www.directadmin.com/features.php?id=801
As of 1.33.3, you can enable a ssl cipher to force SSLv3, and disable SSLv2:
http://www.directadmin.com/features.php?id=957