Running Freeradius 3.2.3 (from freeradius rep) installed with: sudo apt install freeradius freeradius-utils freeradius-freetds After running for 30-60 minutes this happens on all servers (3) (Debian 12-latetst) Thu Dec 14 06:49:32 2023 : Error: rlm_sql_freetds: unable to send command (ct_send()) Thu Dec 14 06:49:32 2023 : ERROR: (571) ERROR: rlm_sql_freetds: Server msg from "mydbserver": severity(5701), number(0), origin(1), layer(1), procedure "none": Changed database context to 'mydb'. Thu Dec 14 06:49:32 2023 : ERROR: (571) ERROR: SQL query failed: server error Thu Dec 14 06:49:32 2023 : Auth: (571) Login incorrect (rlm_sql_freetds: Server msg from "mydbserver": severity(5701), number(0), origin(1), layer(1), procedure "none": Changed database context to 'mydblog'.): [327700051207842] (from client 192.168.3.161/32 port 0 cli 327700051207842) Thu Dec 14 06:49:32 2023 : Auth: (572) Login OK: [327700050547002] (from client 192.168.3.161/32 port 0 cli 327700050547002) Thu Dec 14 06:49:33 2023 : Auth: (573) Login OK: [327700050626183] (from client 192.168.3.161/32 port 0 cli 327700050626183) Thu Dec 14 06:49:33 2023 : Auth: (574) Login OK: [327700051319260] (from client 192.168.3.161/32 port 0 cli 327700051319260) Thu Dec 14 06:49:34 2023 : Auth: (575) Login OK: [327700051047968] (from client 192.168.3.161/32 port 0 cli 327700051047968) Thu Dec 14 06:49:35 2023 : Error: rlm_sql_freetds: unable to send command (ct_send()) etc etc And start repeating like this forever. Most successful, some not. Restarting freeradius solves it directly. At that exact same moment my old centos server CAN connect with no issues to that same db for years already. I'm clueless whats going on here. But im almost sure it must be something local. Changing start servers did not help. Issue stays. freetds.conf # A typical Microsoft Azure SQL [myserver] host = mydb.database.windows.net port = 1433 tds version = 7.3 database = mydb Note that 7.4 does not connect but 7.3 or lower connects. My Setup is a default as possible with 1 sql query that does accept for unit or not. freeradius-freetds seems to install: freetds-common/stable,now 1.3.17+ds-2 all [installed,automatic] Not sure what to do here to use latest from Freetds (1.4.1) Any suggestions? Thanks, Olaf