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Ethereal_96320's avatar
Ethereal_96320
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Oct 15, 2012

distinguish between Citrix client and any browser

Hello folks

 

 

Supposing that I am not an iRules guru, I will ask for help here.

 

Basically the goal of my mission would be blocking the access to the Citrix portal from the browser (using https://myentrypoint.org) but allow the Citrix client (using the same URL).

 

I suppose that I should use the user agent or else, but sniffing the packets in both attempts I couldn’t figure it out a discriminating element or else.

 

Did someone has an idea or already handled this situation?

 

 

Regards

 

Vicentiu

 

application delivery
dev
devops
iRules

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  • Michael_Yates's avatar
    Michael_Yates
    Icon for Nimbostratus rankNimbostratus
    Oct 15, 2012
    Hi Ethereal,

    You should be able to trigger an event based on the User-Agent contained within the HTTP::header, but I would suggest creating an iRule that would just monitor the incoming User-Agents at first (so that you can catch all of the User-Agents that you do not want to block and use the results to make an exclusion list).

    Example: CitrixReciever

    You could start with something like this: 

     
when HTTP_REQUEST {
switch -glob [HTTP::header User-Agent] {
"*MSIE 7.0*" -
"*MSIE 6.0*" -
"*MSIE 5.*" -
"*MSIE 4.*" -
"*Safari*" -
"*Firefox*" -
"*MSRPC*" {
log local0. "Known Browsers to eventuall block."
}
"*CitrixReciever*" {
log local0. "Known Citrix Client"
}
default {
log local0. "Unkown User-Agent: [HTTP::header User-Agent]"
}
}
}

    After you have logged enough you can change the logging behavior to redirect, blocking, reject, drop or whatever action you like.

    I would also suggest these as additional reading. They discuss using the User-Agent as well:

    Split out clients using the Citrix Receiver w/ iRule

    Redirect based on user browser (mobile)

    Hope this helps.
  • Ethereal_96320's avatar
    Ethereal_96320
    Icon for Nimbostratus rankNimbostratus
    Oct 16, 2012
    Hi Michael

     

     

    You're right. I have sniffed on the client side where due to HTTPS encryption I wasn't able to see anything.

     

    I will try to "tcpdump" on the F5 and figure it out as a first step what is the exact string for the Citrix Client, then logging for a while is a good idea.

     

    Thank you very much for tips.

     

     

    Vicentiu