# [ASP_IDS_SYN_COOKIE_ON](https://apps.juniper.net/syslog-explorer/?msg=ASP_IDS_SYN_COOKIE_ON) ## SYSLOG Details - **Message**: Host destination-address, SYN-COOKIE protection activated - **Help**: IDS activated SYN cookie protection - **Description**: Intrusion detection services (IDS) activated SYN cookie protection for the indicated destination address, because it learned from the stateful firewall that the rate of certain events exceeded the threshold set by the 'threshold' statement at the [edit services ids rule <rule-name> term <term-name> then syn-cookie] hierarchy level. The events include the ones reported by the ASP_IDS_TCP_SYN_ATTACK, ASP_SFW_SYN_DEFENSE, and ASP_SFW_TCP_SCAN system log messages. When SYN cookie protection is activated for a flow to a destination and the TCP handshake has not completed, the stateful firewall generates a SYN/ACK packet for each SYN packet directed to the destination. - **Type**: Event: This message reports an event, not an error - **Severity**: error - **Cause**: - - **Action**: - - **Attributes**: destination-address - **Facility**: LOG_PFE ## Found this message in the following releases: - [Junos OS 26.2R1](https://apps.juniper.net/syslog-explorer/?msg=ASP_IDS_SYN_COOKIE_ON&sw=Junos%20OS&rel=26.2R1) - [Junos OS 25.4R1](https://apps.juniper.net/syslog-explorer/?msg=ASP_IDS_SYN_COOKIE_ON&sw=Junos%20OS&rel=25.4R1) - [Junos OS 25.2R2](https://apps.juniper.net/syslog-explorer/?msg=ASP_IDS_SYN_COOKIE_ON&sw=Junos%20OS&rel=25.2R2) - [Junos OS 25.2R1](https://apps.juniper.net/syslog-explorer/?msg=ASP_IDS_SYN_COOKIE_ON&sw=Junos%20OS&rel=25.2R1) - [Junos OS 24.4R2](https://apps.juniper.net/syslog-explorer/?msg=ASP_IDS_SYN_COOKIE_ON&sw=Junos%20OS&rel=24.4R2) - [Junos OS 24.4R1](https://apps.juniper.net/syslog-explorer/?msg=ASP_IDS_SYN_COOKIE_ON&sw=Junos%20OS&rel=24.4R1) - [Junos OS 24.2R2](https://apps.juniper.net/syslog-explorer/?msg=ASP_IDS_SYN_COOKIE_ON&sw=Junos%20OS&rel=24.2R2) - [Junos OS 24.2R1](https://apps.juniper.net/syslog-explorer/?msg=ASP_IDS_SYN_COOKIE_ON&sw=Junos%20OS&rel=24.2R1) - [Junos OS 23.4R2](https://apps.juniper.net/syslog-explorer/?msg=ASP_IDS_SYN_COOKIE_ON&sw=Junos%20OS&rel=23.4R2) - [Junos OS 23.4R1](https://apps.juniper.net/syslog-explorer/?msg=ASP_IDS_SYN_COOKIE_ON&sw=Junos%20OS&rel=23.4R1) - [Junos OS 23.2R2](https://apps.juniper.net/syslog-explorer/?msg=ASP_IDS_SYN_COOKIE_ON&sw=Junos%20OS&rel=23.2R2) - [Junos OS 23.2R1](https://apps.juniper.net/syslog-explorer/?msg=ASP_IDS_SYN_COOKIE_ON&sw=Junos%20OS&rel=23.2R1) - [Junos OS 22.4R3](https://apps.juniper.net/syslog-explorer/?msg=ASP_IDS_SYN_COOKIE_ON&sw=Junos%20OS&rel=22.4R3) - [Junos OS 22.4R2](https://apps.juniper.net/syslog-explorer/?msg=ASP_IDS_SYN_COOKIE_ON&sw=Junos%20OS&rel=22.4R2) - [Junos OS 22.4R1](https://apps.juniper.net/syslog-explorer/?msg=ASP_IDS_SYN_COOKIE_ON&sw=Junos%20OS&rel=22.4R1) - [Junos OS 22.2R3](https://apps.juniper.net/syslog-explorer/?msg=ASP_IDS_SYN_COOKIE_ON&sw=Junos%20OS&rel=22.2R3) - [Junos OS 22.2R2](https://apps.juniper.net/syslog-explorer/?msg=ASP_IDS_SYN_COOKIE_ON&sw=Junos%20OS&rel=22.2R2) - [Junos OS 22.2R1](https://apps.juniper.net/syslog-explorer/?msg=ASP_IDS_SYN_COOKIE_ON&sw=Junos%20OS&rel=22.2R1)