Office network very slow, show logging display ""aggressive and calming down" error

musikman1988

Dear All,

Our office have 100 users. In recent, network was very slow, users access the website was very slowly. But they can ping website name successful.

I log on the egde router to "show logging", and it display some error as below:

My question is whether network has DOS attack? If so, what should I to do solve this issue?

Thanks in advance!!

BR Frank

Our network topology is ISP

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2900

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3750

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2960X stack *3

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LAP

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end users

Error log as below:

May 16 08:13:55.969: %FW-4-TCP_OoO_SEG: Dropping TCP Segment: seq:2102491905 1064 bytes is out-of-order; expected seq:2102404865. Reason: TCP reassembly queue overflow - session 10.24.246.44:64405 to 140.207.195.36:80
May 16 08:14:43.604: %FW-3-RESPONDER_WND_SCALE_INI_NO_SCALE: Dropping packet - Invalid Window Scale option for session 10.24.246.53:55552 to 58.221.72.180:80 [Initiator(flag 0,factor 0) Responder (flag 1, factor 9)]
May 16 08:15:07.972: %FW-4-ALERT_OFF: calming down, count (46/900) current 1-min rate: 1796
May 16 08:15:10.344: %FW-4-ALERT_ON: getting aggressive, count (56/1000) current 1-min rate: 2001
May 16 08:15:54.052: %FW-4-ALERT_OFF: calming down, count (44/900) current 1-min rate: 1793
May 16 08:15:56.912: %FW-4-ALERT_ON: getting aggressive, count (59/1000) current 1-min rate: 2001