Checking if anybody had the same problem and how it was dealt with.
Recently during a normal load smsbox was stopped and restarted itself, resulting in approximately 1 min downtime. Checked the logs. journalctl log: kernel: TCP: request_sock_TCP: Possible SYN flooding on port 13002. Sending cookies. Check SNMP counter. smsbox log: 2024-08-20 02:02:06 [950639] [3] INFO: smsbox: Got HTTP request </cgi-bin/sendsms> from <XXX.XX.XX.XXX> 2024-08-20 02:02:06 [950639] [3] INFO: sendsms used by <smsuser> 2024-08-20 02:02:06 [950639] [9] ERROR: Error writing 708 octets to fd 116: 2024-08-20 02:02:06 [950639] [9] ERROR: System error 104: Connection reset by peer 2024-08-20 02:02:06 [950639] [3] INFO: sendsms sender:<smsuser:XXXXX> (XXX.XX.XX.XXX) to:<XXXXXXXXXXX> msg:<XXXXXXXX> 2024-08-20 02:02:06 [950639] [9] ERROR: Error writing 708 octets to fd 116: 2024-08-20 02:02:06 [950639] [9] ERROR: System error 32: Broken pipe 2024-08-20 02:02:06 [950639] [9] ERROR: Couldn't send request to <http://XXXX> 2024-08-20 02:02:06 [950639] [9] PANIC: gwlib/conn.c:859: conn_unregister: Assertion `conn != NULL' failed. 2024-08-20 02:02:06 [950639] [5] INFO: Starting delivery report <smsuser> from <XXXXX> 2024-08-20 02:02:06 [950639] [3] INFO: smsbox: Got HTTP request </cgi-bin/sendsms> from <XXX.XX.XX.XXX> 2024-08-20 02:02:06 [950639] [3] INFO: sendsms used by <smsuser> 2024-08-20 02:02:06 [950639] [5] INFO: Starting delivery report <smsuser> from <XXXXX> 2024-08-20 02:02:06 [950639] [9] PANIC: /usr/sbin/smsbox(gw_backtrace+0xe0) [0x564373b1a3d0] 2024-08-20 02:02:06 [950639] [9] PANIC: /usr/sbin/smsbox(gw_panic+0x163) [0x564373b1a543] 2024-08-20 02:02:06 [950639] [9] PANIC: /usr/sbin/smsbox(+0x4e4f2) [0x564373b174f2] 2024-08-20 02:02:06 [950639] [9] PANIC: /usr/sbin/smsbox(+0x44562) [0x564373b0d562] 2024-08-20 02:02:06 [950639] [9] PANIC: /usr/sbin/smsbox(+0x46b35) [0x564373b0fb35] 2024-08-20 02:02:06 [950639] [9] PANIC: /lib/x86_64-linux-gnu/libc.so.6(+0x89134) [0x7f7b5b4a8134] 2024-08-20 02:02:06 [950639] [9] PANIC: /lib/x86_64-linux-gnu/libc.so.6(+0x1097dc) [0x7f7b5b5287dc] 2024-08-20 02:02:06 [950639] [3] INFO: smsbox: Got HTTP request </cgi-bin/sendsms> from <XXX.XX.XX.XXX> 2024-08-20 02:03:06 [950689] [0] INFO: Added logfile `/var/log/kannel/smsbox.log' with level `1'. 2024-08-20 02:03:06 [950689] [0] INFO: Logging accesses to '/var/log/kannel/access.log'. 2024-08-20 02:03:06 [950689] [0] INFO: Started access logfile `/var/log/kannel/access.log'. 2024-08-20 02:03:06 [950689] [0] INFO: HTTP: Opening server at port 13002. 2024-08-20 02:03:06 [950689] [0] INFO: Set up send sms service at port 13002 2024-08-20 02:03:06 [950689] [0] INFO: Using HTTP request queueing with 3 retries, 5s delay. 2024-08-20 02:03:06 [950689] [0] INFO: Connected to bearerbox at localhost port 13001. 2024-08-20 02:03:06 [950689] [5] INFO: Starting delivery report <smsuser> from <XXXXX> Thanks, Lelik.
