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Marco_Lei's avatar
Marco_Lei
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Dec 05, 2018

Create iRule condition with matching client IP from multiple IP subnet

I need to create an iRule to check if a DNS query domain name matches a preconfigured list of domain name, AND client IP matches one of following network:

172.18.9.0/24
172.25.10.0/24

The iRule that I thought to be usable is:

when DNS_REQUEST {
set filter_list {
"abctest.example.com" 

}
if  { [lsearch -exact $filter_list [DNS::question name]] ne -1 && {![IP::addr [IP::client_addr] equals 172.18.9.0/24] ||![IP::addr [IP::client_addr] equals 172.25.10.0/24]}} {
    DNS::header rcode NXDOMAIN
    DNS::return
}
}

However, this condition doesn't work. DNS query that is not in above network will still have timeout message, instead of directly receive NXDomain response. I would like to know what I done wrong in my iRule condition, and feasible solution to make this iRule work properly.

  • I would use data-groups for host and IP matching, it's more elegant. And try to add some logging to the irule to help you see what is going wrong.

     

1 Reply

  • I would use data-groups for host and IP matching, it's more elegant. And try to add some logging to the irule to help you see what is going wrong.