I don't know if this is an attack or something else. My servers have encountered SYN flood for couple weeks, like followings:
I've blocked the IP in firewall, but it still keeps sending SYN packet till now.
For only one IP, I don't think it is an attack, but I am wondering if there is something else I should aware of or actions I should take, since I am a newbie in FreeBSD.
Thank you for any suggestion.
Code:
+TCP: [46.105.180.237]:17202 to [60.250.122.41]:80; syncache_timer: Retransmits exhausted, giving up and removing syncache entry
+TCP: [46.105.180.237]:9827 to [60.250.122.41]:80 tcpflags 0x10<ACK>; syncache_expand: Segment failed SYNCOOKIE authentication, segment rejected (probably spoofed)
+TCP: [46.105.180.237]:32146 to [60.250.122.41]:80 tcpflags 0x10<ACK>; syncache_expand: Segment failed SYNCOOKIE authentication, segment rejected (probably spoofed)
+TCP: [46.105.180.237]:11845 to [60.250.122.41]:80; syncache_timer: Response timeout, retransmitting (2) SYN|ACK
+TCP: [46.105.180.237]:53448 to [60.250.122.41]:80; syncache_timer: Response timeout, retransmitting (3) SYN|ACK
+TCP: [46.105.180.237]:15907 to [60.250.122.41]:80 tcpflags 0x10<ACK>; syncache_expand: Segment failed SYNCOOKIE authentication, segment rejected (probably spoofed)
+TCP: [46.105.180.237]:9827 to [60.250.122.41]:80 tcpflags 0x10<ACK>; syncache_expand: Segment failed SYNCOOKIE authentication, segment rejected (probably spoofed)
+TCP: [46.105.180.237]:12469 to [60.250.122.41]:80; syncache_timer: Response timeout, retransmitting (1) SYN|ACK
+TCP: [46.105.180.237]:48155 to [60.250.122.41]:80; syncache_timer: Retransmits exhausted, giving up and removing syncache entry
+TCP: [46.105.180.237]:15907 to [60.250.122.41]:80 tcpflags 0x10<ACK>; syncache_expand: Segment failed SYNCOOKIE authentication, segment rejected (probably spoofed)
I've blocked the IP in firewall, but it still keeps sending SYN packet till now.
For only one IP, I don't think it is an attack, but I am wondering if there is something else I should aware of or actions I should take, since I am a newbie in FreeBSD.
Thank you for any suggestion.