Creating LDAP Authentication Rule fails when hostname is used

[Chaos823]

PacketFence version
15.1.0

Describe the bug
Using the FQDN of the ldap Server in LDAP or Active Directory Authentication Source results in the Test returning Can't connect to server or bind with '<binduser>' on <ldapserver>:389.

The Logs show the following:

2026-06-19T10:25:21.438229+02:00 srv-pf-v15 pfperl-api-docker-wrapper[648127]: pfperl-api(9) WARN: [mac:[undef]] [ADVerwaltung] <ldapserver> detected as dead, switching to next server (pf::Authentication::Source::LDAPSource::__ANON__)
2026-06-19T10:25:21.438668+02:00 srv-pf-v15 pfperl-api-docker-wrapper[648127]: pfperl-api(9) ERROR: [mac:[undef]] [ADVerwaltung] Unable to connect to any LDAP server, will try while ignoring the dead servers detection (pf::Authentication::Source::LDAPSource::_connect)
2026-06-19T10:25:21.446354+02:00 srv-pf-v15 pfperl-api-docker-wrapper[648127]: pfperl-api(9) ERROR: [mac:[undef]] Resolved <ldapserver> to ip <ipaddress> through pfdns-connector is not part of any pfconnector networks (pf::factory::connector::resolve)
2026-06-19T10:25:21.447986+02:00 srv-pf-v15 pfperl-api-docker-wrapper[648127]: pfperl-api(9) WARN: [mac:[undef]] Use of uninitialized value $dest_ip in concatenation (.) or string at /usr/local/pf/lib/pf/Authentication/Source/LDAPSource.pm line 282.
2026-06-19T10:25:21.452123+02:00 srv-pf-v15 pfperl-api-docker-wrapper[648127]: pfperl-api(9) ERROR: [mac:[undef]] Error binding to <ipaddress>:36431: 'Unexpected EOF' (pf::LDAP::log_error_msg)
2026-06-19T10:25:21.452235+02:00 srv-pf-v15 pfperl-api-docker-wrapper[648127]: pfperl-api(9) WARN: [mac:[undef]] [ADVerwaltung] Unable to connect to <ldapserver> (pf::Authentication::Source::LDAPSource::__ANON__)
2026-06-19T10:25:21.452235+02:00 srv-pf-v15 pfperl-api-docker-wrapper[648127]: pfperl-api(9) ERROR: [mac:[undef]] [ADVerwaltung] Unable to connect to any LDAP server (pf::Authentication::Source::LDAPSource::_connect)
2026-06-19T10:25:21.452797+02:00 srv-pf-v15 pfperl-api-docker-wrapper[648127]: pfperl-api(9) WARN: [mac:[undef]] [ADVerwaltung] Unable to connect to any LDAP server (pf::Authentication::Source::LDAPSource::test)

To Reproduce
Steps to reproduce the behavior:

1. Go to /admin#/configuration/sources'
2. Create internal source for LDAP
3. Use hostname in the host field and configure Bind dn
4. Click on Test

Expected behavior
The Hostname should be resolved properly or documentation for configuring the pfdns-connector should be added, if needed.

Desktop (please complete the following information):

• OS: Windows 11
• Browser Firefox
• Version [e.g. 22]

Additional context
This still worked with Packetfence 15.0, but that version didn't have the pfdns-connector yet. The LDAP Server is in the same subnet as the management interface.