Hi, freeradius team! I know, this "Ignoring duplicate packet" topic has been discussed for a long time again and again. I see that in a special configuration: - FreeRADIUS Version 3.0.17 on Ubuntu - ActiveDirectory on Winserver 2012 R2 - authentication via ntlm_auth - post-auth via LDAP (group ownership etc) - 15 brand-new Cisco/Meraki-WLAN-APs in network - all Cisco/Meraki-WLAN-APs are controlled by a central web-based Meraki dashboard Everything works fine, there are no user complaints so far. BUT: The central Meraki dashboard has a built-in test function to check all managed NAS if they are able to communicate with radius server. So I have to provide an existing user/password and the dashboard triggers each NAS to check for freeradius authentication with same credentials. In this scenario I run into the "Ignoring duplicate packet" issue (see freeradius log part below) which let the Meraki dashboard reports some NAS as failing. The count of failing NASs and the failing NASs are varying . However when I disable the LDAP post-auth section everything is fine. Wed Feb 26 14:21:05 2020 : Info: rlm_ldap (ldap): Opening additional connection (17641), 1 of 30 pending slots used Wed Feb 26 14:21:05 2020 : Info: rlm_ldap (ldap): Deleting connection (17640) - Was referred to a different LDAP server Wed Feb 26 14:21:05 2020 : Info: Need 1 more connections to reach min connections (3) Wed Feb 26 14:21:05 2020 : Info: rlm_ldap (ldap): Opening additional connection (17642), 2 of 31 pending slots used Wed Feb 26 14:21:05 2020 : Error: (69437) Ignoring duplicate packet from client ZI-110 port 54766 - ID: 8 due to unfinished request in component post-auth module ldap Wed Feb 26 14:21:05 2020 : Error: (69438) Ignoring duplicate packet from client ZI-112 port 42248 - ID: 8 due to unfinished request in component post-auth module ldap Wed Feb 26 14:21:05 2020 : Info: rlm_ldap (ldap): Deleting connection (17638) - Was referred to a different LDAP server Wed Feb 26 14:21:07 2020 : Info: rlm_ldap (ldap): Opening additional connection (17643), 1 of 30 pending slots used Wed Feb 26 14:21:07 2020 : Error: (69446) Ignoring duplicate packet from client ZI-120 port 58022 - ID: 6 due to unfinished request in component authenticate module eap_peap Wed Feb 26 14:21:07 2020 : Error: (69453) Ignoring duplicate packet from client ZI-216 port 37434 - ID: 6 due to unfinished request in component authenticate module eap_peap Wed Feb 26 14:21:08 2020 : Error: (69460) Ignoring duplicate packet from client ZI-012 port 49893 - ID: 6 due to unfinished request in component authenticate module eap_peap Wed Feb 26 14:21:08 2020 : Info: rlm_ldap (ldap): Deleting connection (17642) - Was referred to a different LDAP server Wed Feb 26 14:21:08 2020 : Info: Need 1 more connections to reach min connections (3) Wed Feb 26 14:21:08 2020 : Info: rlm_ldap (ldap): Opening additional connection (17644), 1 of 30 pending slots used Wed Feb 26 14:21:08 2020 : Info: rlm_ldap (ldap): Deleting connection (17641) - Was referred to a different LDAP server Wed Feb 26 14:21:08 2020 : Info: rlm_ldap (ldap): Opening additional connection (17645), 1 of 30 pending slots used Wed Feb 26 14:21:09 2020 : Info: rlm_ldap (ldap): Deleting connection (17643) - Was referred to a different LDAP server I'm pretty sure the root cause is related to general network and/or LDAP performance. Actions I will take are: - let network admin check the network and DC/AD server performance - review my freeradius LDAP queries if they are specific enough (reducing the amount of data they generate) But I have some questions to freeradius team related to that: I have a single freeradius server and a single DC/AD server. 1) Why does freeradius open and close LDAP connections pretty often? Isn't one permanently open connection good enough? 2) What does this message mean: Info: rlm_ldap (ldap): Deleting connection (17640) - Was referred to a different LDAP server There is just one LDAP server! I started a debug session and found this matching part in debug log: (25) ldap: User object found at DN "CN=jasmin hahn,OU=Schueler,DC=moritz,DC=local" (25) ldap: EXPAND (samaccountname=%{mschap:User-Name}) (25) ldap: --> (samaccountname=jasmin-hahn) (25) ldap: Waiting for bind result... (25) ldap: Bind successful (25) ldap: Performing search in "DC=moritz,DC=local" with filter "(samaccountname=jasmin-hahn)", scope "sub" (25) ldap: Waiting for search result... rlm_ldap (ldap): Rebinding to URL ldap://ForestDnsZones.moritz.local/DC=ForestDnsZones,DC=moritz,DC=local rlm_ldap (ldap): Waiting for bind result... rlm_ldap (ldap): Rebinding to URL ldap://DomainDnsZones.moritz.local/DC=DomainDnsZones,DC=moritz,DC=local rlm_ldap (ldap): Waiting for bind result... rlm_ldap (ldap): Rebinding to URL ldap://moritz.local/CN=Configuration,DC=moritz,DC=local rlm_ldap (ldap): Waiting for bind result... rlm_ldap (ldap): Bind successful rlm_ldap (ldap): Bind successful rlm_ldap (ldap): Bind successful (25) ldap: Adding cacheable group object memberships (25) ldap: &control:LDAP-Group += "OU=Schueler" (25) ldap: Processing user attributes (25) ldap: WARNING: No "known good" password added. Ensure the admin user has permission to read the password attribute (25) ldap: WARNING: PAP authentication will *NOT* work with Active Directory (if that is what you were trying to configure) *rlm_ldap (ldap): Deleting connection (3) - Was referred to a different LDAP server* (I'm aware I cannot get passwd from AD, that's why I use ntlm_auth. This is not the topic I want to ask here. Or is it related??) 3) In my special case (self test by Meraki dashboard) I check same user from all NASs within a short timeframe. So freeradius should provide always same feedback. Could the freeradius flow be shortened by a cache mechanism? Thanks a lot! Uwe