new Authentication Provider LDAP fail on Linux Ubuntu 24.04

Problem reported by Markus Goessinger - 6/6/2025 at 12:43 AM

Submitted

we have a new blank installation of SmarterMail on Linux

SmarterMail Version: 9280 (Mai 29, 2025)

Ubuntu 24.04.2 LTS

LDAP Server Windows Domain Controler 2016

when we try to create a new Authentication Provider LDAP

when we fill out the form and click on Continue

we got the error message "The type initializer for 'Ldap' threw an exception."

we test connection to ip address and port 389 from linux shell, it's posible

we installed ldapsearch and test username and credentials ist okay

no mater when we try wrong ip address or wrong credentials always the same error message.

so just for testing we installed SmarterMail on a Windows server to try the same settings for LDAP it works on Windows , but i still find no way to get it working on Linux.

has anyone LDAP Authentication working on Ubuntu or an other Linux?

3 Replies

Reply to Thread

Markus Goessinger Replied

6/7/2025 at 6:41 AM

so now i have make a new blank installation of SmarterMail and Linux

ubuntu-22.04.5-live-server-amd64

SmarterMail Version: 9245

add a new Authentication Provider LDAP is working

import Acounts from Authentication Provider LDAP is working

then i make an Update SmarterMail Version: 9245 to 9280

add a new Authentication Provider LDAP is working

import Acounts from existing and new Authentication Provider LDAP is working

then i make an relese upgrade from Ubunto to 24.04

New release '24.04.2 LTS' available.
Run 'do-release-upgrade' to upgrade to it.

add a new Authentication Provider LDAP is NOT working

import Acounts from existing Authentication Provider LDAP is NOT working

so i think its a fakt:

Authentication Provider LDAP is working on Ubuntu 22.04

Authentication Provider LDAP is NOT working on Ubuntu 24.04

Kyle Kerst Replied

6/9/2025 at 8:44 AM

Employee Post

Thanks for reporting this Markus, I believe there was in fact a change in the ldap provider between these two versions of Ubuntu. We'll work on getting this confirmed in-house and escalated for you.

Kyle Kerst Lead Internal Network/System Administrator SmarterTools Inc. smartertools.com

Kyle Kerst Replied

6/10/2025 at 4:13 PM

Employee Post

Hey Markus! After posting my response here yesterday I checked in with Ray (in Support here) as I vaguely remembered him having run into this previously. We did a little research on the development escalation at the time and it looks like this was found to be an issue with the ldap DLL version in use in .NET on Linux, rather than an issue with SmarterMail specifically.

The Microsoft .NET hub pages discussing the issue at the time seemed to indicate Microsoft wasn't planning on resolving it either, so their recommended workaround is downgrading to the ldap DLL version used in the previous version. I believe Ray had some luck doing so but the process for getting that implemented might vary depending on your versions.

From what I understand you just need to manually install and reference the LDAP DLL 2.5 instead of 2.6. This is discussed in more detail here where an admin had a similar issue under a different product: https://askubuntu.com/questions/1540581/libldap-2-5-on-ubuntu-24-04

Kyle Kerst Lead Internal Network/System Administrator SmarterTools Inc. smartertools.com

Back to Community Threads

Please leave this box unchecked

Reply to Thread

Enter the verification text