Forum Discussion

f5rocks_86658's avatar
f5rocks_86658
Icon for Nimbostratus rankNimbostratus
Feb 15, 2019

ASM DoS detection

Does it mean that DoS would be detected if requests per source IP reached to 200 per second? What's the significance of 40 tps here?

 

 

ASM Advanced WAF
security
  • leonline_225556's avatar
    leonline_225556
    Icon for Altostratus rankAltostratus
    Feb 16, 2019

    Hi f5rocks,

     

    The ASM DoS feature measures the TPS every 10 seconds and calculates the average for the past hour.

     

    DoS will be detected when an absolute TPS value of 200 is reached, but also when an absolute TPS value of 40 is reached AND an increase of 500% is detected.

     

    Example:

     

    • Average TPS: 75 (for the past hour)
    • Last TPS measured: 600
    • TPS increased by: ((600 - 75) / 75) * 100 = 700%

    Based on your screenshot DoS will be detected because TPS increased by 700% (> 500%) and absolute value is 600 TPS (> 40 TPS).

     

    Leon

     

  • spalande's avatar
    spalande
    Icon for Nacreous rankNacreous
    Feb 16, 2019

    Thanks. But if last TPS is600, doesn't DoS will be detected immediately as it's higher than absolute threshold (200 TPS). My point was if both values come to same TPS rate (i.e increased TPS% or absolute Threshold) so not sure why two conditions are given. Also hope as name suggests these are for single source IP.