HI ASM experts, I am seeing traffic getting blocked due to the "Illegal cookie length violation" . System configured: 8192 bytes, received 8452. I am running 11.5.1 HF7. I tried to increase the cookie length by going to the policy and selecting advanced, BUT it gave me an error that the max allowed is 8192 bytes. What is the work around for this? This seems to be a legit GET request.

Hi, 8192 bytes is the default length, not the max allowed in general. I will try it on my lab and give you a feedback

8192 Is indeed the maximum and I think you only have 2 workarounds - disable the violation, or write a custom iRule. Disabling the violation itself would probably make the most sense here. Go to policy blocking settings, and un-tick the 'learn/alarm/block' boxes under Illegal cookie length violation. Save and apply changes.

In fact, that's true. 8192 bytes is the maximum length you can define for header and cookies. This is a limit that include name+value. You can change this setting by Any if you have headers that exceed this max length

illegal cookie length: ASM violation

16 Replies

Yann_Desmarest
Cirrus
Jun 20, 2016
Hi,

8192 bytes is the default length, not the max allowed in general.

I will try it on my lab and give you a feedback
- Yann_Desmarest
  Cirrus
  Jun 20, 2016
  In fact, that's true. 8192 bytes is the maximum length you can define for header and cookies. This is a limit that include name+value. You can change this setting by Any if you have headers that exceed this max length
Yann_Desmarest_
Nacreous
Jun 20, 2016
Hi,

8192 bytes is the default length, not the max allowed in general.

I will try it on my lab and give you a feedback
- Yann_Desmarest_
  Nacreous
  Jun 20, 2016
  In fact, that's true. 8192 bytes is the maximum length you can define for header and cookies. This is a limit that include name+value. You can change this setting by Any if you have headers that exceed this max length
Hannes_Rapp_162
Nacreous
Jun 20, 2016
8192 Is indeed the maximum and I think you only have 2 workarounds - disable the violation, or write a custom iRule. Disabling the violation itself would probably make the most sense here.

Go to policy blocking settings, and un-tick the 'learn/alarm/block' boxes under
Illegal cookie length
violation. Save and apply changes.
- MSZ
  Nimbostratus
  Jul 23, 2017
  What about 2048 bytes
- Hannes_Rapp_162
  Nacreous
  Jul 23, 2017
  @MSZ - Can't understand the question
- MSZ
  Nimbostratus
  Jul 23, 2017
  when I created the ASM policy longtime back I didn't notice the value of Max. cookie header length (It comes on Policy properties page). As per documentation it is any by default. But in my case I am able to see the value like 2048. I want to know how this value comes and where ?
Hannes_Rapp
Nimbostratus
Jun 20, 2016
8192 Is indeed the maximum and I think you only have 2 workarounds - disable the violation, or write a custom iRule. Disabling the violation itself would probably make the most sense here.

Go to policy blocking settings, and un-tick the 'learn/alarm/block' boxes under
Illegal cookie length
violation. Save and apply changes.
- MSZ
  Nimbostratus
  Jul 23, 2017
  What about 2048 bytes
- Hannes_Rapp
  Nimbostratus
  Jul 23, 2017
  @MSZ - Can't understand the question
- MSZ
  Nimbostratus
  Jul 23, 2017
  when I created the ASM policy longtime back I didn't notice the value of Max. cookie header length (It comes on Policy properties page). As per documentation it is any by default. But in my case I am able to see the value like 2048. I want to know how this value comes and where ?