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New Member

ACE Module Cookie Parsing causes Reset Connection

I am trying to upgrade my ACE Modules from A2(1.3) to A2(3.2) . Unfortunately, the cookie parsing breaks when there are illegal characters and causes a connection reset (RST) when there is an invalid cookie, but only on code later than A2(1.3).

The cookie in question is being passed by a third party so making them change the cookie is not necessarily do-able. The cookie has the following value:

Cookie:  CurrentUser={"UserKey":{"Key":"anonymous"},"LastUpdated":"10/13/2010 1:35:52 PM"}

We are using the following parameter map:

parameter-map type http CASE_PARAM
  case-insensitive
  persistence-rebalance
  set header-maxparse-length 20480
  length-exceed continue

On the older code, the request is passed on to the server.

Is there a setting similar to "length-exceed continue" that I can give the ACE to tell it to ignore cookies it cannot parse?

Everyone's tags (2)
5 REPLIES
Cisco Employee

Re: ACE Module Cookie Parsing causes Reset Connection

Do you have HTTP inspection configured ?  If yes, you need to remove it.

Does your serverfarm has a 'class-default' ? if not you need to create one so that it can handle parse errors.

Gilles.

New Member

Re: ACE Module Cookie Parsing causes Reset Connection

HTTP inspection is not enabled.

Did you mean adding a class-default to the policy-map?

Adding it to the policy-map does make it match the class-default. Unfortunately, cookie parse errors result in the inability to parse both the cookie and the host header as well. It seems that rather than just failing to parse the cookie and being unable to do sticky matching - it completely fails the entire header parsing.

Here's our setup:

rserver host test1
  ip address 192.168.1.101
  inservice

rserver host test2
   ip address 192.168.1.102
   inservice

rserver host test3
   ip address 192.168.1.103
   inservice

rserver host test4
   ip address 192.168.1.104
   inservice

serverfarm host auto
  probe HTTP-diagnostic
  rserver test1
    inservice
  rserver test2
    inservice

serverfarm host news
  probe HTTP-diagnostic
  rserver test3
    inservice
  rserver test4
    inservice

sticky http-cookie autoCookie auto-cookie
  cookie insert browser-expire
  replicate sticky
  serverfarm auto
sticky http-cookie newsCookie news-cookie
  cookie insert browser-expire
  replicate sticky
  serverfarm news

class-map type http loadbalance match-any auto
  2 match http header Host header-value "www.auto.local"
  3 match http header Host header-value "auto.local"

class-map type http loadbalance match-any news
   2 match http header Host header-value "www.news.local"
   3 match http header Host header-value "news.local"

class-map match-all prod_VIP
  2 match virtual-address XXX.XXX.XXX.XXX tcp eq www

policy-map type loadbalance first-match prod_POLICY
  class auto
    sticky-serverfarm auto-cookie
  class news
    sticky-serverfarm news-cookie
  class class-default
    sticky-serverfarm auto-cookie

policy-map multi-match aggregate-slb-apps
  class prod_VIP
    loadbalance vip inservice
    loadbalance policy prod_POLICY
    loadbalance vip icmp-reply active
    loadbalance vip advertise
    appl-parameter http advanced-options CASE_PARAM

Cisco Employee

Re: ACE Module Cookie Parsing causes Reset Connection

Under the class-default configure a simple serverfarm.

When there is a parse error, ace falls back to L4 mode so it stops parsing and just tries to do a normal loadbalancing operation if one is available.

What has changed in later version is that now the "," is considered as a cookie separator (as defined in RFC).

Therefore, the cookie is splitted in 2 at the coma and the part following the coma is considered invalid.

If possible, try to change the cookie on the server since this cookie is illegal per RFC anyway.

Gilles

New Member

Re: ACE Module Cookie Parsing causes Reset Connection

Bringing back up an old thread, but it looks like A2 (3.3) has a fix for this.

Will cookie-error-ignore fix my issue here?

New Member

Hi Guys,  I was checking and

very helpful.

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