I have made the following observation in my environment and I am struggling to debug & find a resolution. We support a very mixed
environment of LINUX / AIX / SOLARIS / HPUX . Our LDAP is on both Ubuntu or Solaris and all run OpenLDAP.
Since we updated the Ubuntu openssl level for this alert:
https://www.ubuntu.com/usn/usn-3087-2/
Our N-Series servers (ontap Ontap 8.2.4P3 7-Mode) are failing to connect to the Ubuntu OPENLDAP via TLS Now
Dec 20 07:21:50 ldap7 slapd[12921]: conn=3231 fd=25 ACCEPT from IP=9.42.34.211:39304 (IP=0.0.0.0:636)
Dec 20 07:21:50 ldap7 slapd[12921]: conn=3231 fd=25 closed (TLS negotiation failure)
My initial thoughts was that the (CVE-2016-2183) moving DES / 3DES to MEDIUM was the issue, so I extended the
LDAP allowed ciphers include MEDIUM. However TLS negotiation still fails.
Can anyone tell me what ciphers a Ontap client sends to the LDAP server during the TLS handshake so I can test
using :
openssl s_client -connect ldap6:636 -tls1 -cipher AES128-SHA
The theory being if the LDAP is rejecting the ciphers or TLS level the above command would simulate it.
Another option maybe wireshark to see the handshake but as I type this option is not open to me currently/
Any thoughts People ?