LdapErr: In order to perform this operation a successful bind must be completed on the connection

[Alex_Raoul]

Hello All,

I hope you're doing well.

I have this error ([1186] fnbamd_ldap_parse_response-Error 1(000004DC: LdapErr: DSID-0C090D93, comment: In order to perform this operation a successful bind must be completed on the connection., data 0, v4563))  on ldap debug when i try to access one of my sites through IPSec VPN from FortiClient.

I use an AD account for authentication.

For the bind type, It's Regular.

please what is the issue ?

[funkylicious]

have a look at https://community.fortinet.com/t5/FortiGate/Technical-Tip-How-to-troubleshoot-the-Invalid-LDAP-serve... 

[Alex_Raoul]

Thank you for your feedback.
Let me try and get back to you.

[funkylicious]

if you have a IPsec VPN between sites make sure that you have set the source ip ( not mandatory if i recall correctly ) and there are firewall rules on the remote FGT where the LDAP resides where you have granted access to LDAP from the source ip of the remote FGT.

[Alex_Raoul]

Yes @funkylicious,

----> the source server IP has been specified in the LDAP configuration.

----> The server IP source has been Added to the local address of phase 2 VPN IPSec site-to-site.

----> That IP has been authorised to communicate with the LDAP server on the FGT remote site.

I have no IP & port communication issue on both Fortigates, just that error I discovered in LDAP debug.

As suggested in the recommendation you shared, we will open a case at Microsoft support .

As a workaround, I have switched to STARTTLS protocol + CA certificate on LDAP server and the authentication is working well.