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sidiov's avatar
sidiov
Icon for Nimbostratus rankNimbostratus
Aug 23, 2011

Trouble with a irule using a data group

I am attempting to drop several user agent headers that hit a website consistantly with bad traffic, I wanted to use a data group for a list of agents, but when i use it, it drops all connections.

 

 

Here is the data group irule:

 

 

when HTTP_REQUEST { if {[matchclass [string tolower [HTTP::header "User-Agent"]] contains $::danger-user-agents] } { drop } }

 

 

danger-user-agents group contains 2 strings:

 

zmeu

 

black hole

 

 

 

If I manually specify the names it works:

 

 

when HTTP_REQUEST { if { [string tolower [HTTP::header "User-Agent"]] contains "zmeu" } {drop} elseif { [string tolower [HTTP::header User-Agent]] contains "black hole" } {drop} }

 

 

 

What am I doing wrong in the data group version?

 

 

I do have a similar data group working for another site's irule that drops based on uri strings, and that works fine:
application delivery
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devops
iRules
  • hooleylist's avatar
    hooleylist
    Icon for Cirrostratus rankCirrostratus
    Aug 23, 2011
    If you're on 9.4.4 or higher, you should remove the $:: prefix from the datagroup name. If you're on 10.0+ you should use class match instead of matchclass: 

    
when HTTP_REQUEST {
   if {[class match [string tolower [HTTP::header "User-Agent"]] contains danger-user-agents] } { drop }
}

    If you run into issues with drop, try reject instead.

    Aaron
  • hooleylist's avatar
    hooleylist
    Icon for Cirrostratus rankCirrostratus
    Aug 23, 2011
    Actually, the issue is with the hyphens in the datagroup name. Can you change them to underscores or wrap the datagroup name inthe iRule in curly braces: 

    when HTTP_REQUEST {
   if {[class match [string tolower [HTTP::header "User-Agent"]] contains {danger-user-agents}] } { drop }
}

    Or if you change the datagroup name:

    when HTTP_REQUEST {
   if {[class match [string tolower [HTTP::header "User-Agent"]] contains danger_user_agents}] } { drop }
}

    Without the curly braces, the hyphen in TCL (and iRules) breaks up the variable (or class) name.

    Aaron
  • sidiov's avatar
    sidiov
    Icon for Nimbostratus rankNimbostratus
    Aug 23, 2011
    Thanks!

     

    I changed the name and removed the $:: and everything worked. I update to class match as well and everything is good. Thanks.