Mar 27, 2026 - For details about updated CVE-2025-53521 (BIG-IP APM vulnerability), refer to K000156741.

Forum Discussion

dragonflymr's avatar
dragonflymr
Icon for Cirrostratus rankCirrostratus
Dec 07, 2015

Parsing IP to extract subnet

Hi,   I wonder if there is more elegant and fastest way to extract specific part of IP - like get only part of IP up to second dot, third dot.   I know that I can use scan to separate IP in fou...
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StephanManthey's avatar
StephanManthey
Icon for Nacreous rankNacreous
Dec 07, 2015

Perhaps I got your question wrong. Following Vernons solution you can check the following if you already know the relevant networks: 

when CLIENT_ACCEPTED {
    switch [IP::addr [IP::client_addr]] {
        "10.131.131.0/26"   { log local0. "client [IP::client_addr] in 10.131.131.0/25 detected"
        "10.131.131.64/26"  { log local0. "client [IP::client_addr] in 10.131.131.64/25 detected"
        "10.131.131.128/26" { log local0. "client [IP::client_addr] in 10.131.131.128/25 detected"
        "10.131.131.192/26" { log local0. "client [IP::client_addr] in 10.131.131.192/25 detected"
    }
}

Thanks, Stephan

PS: I am pretty sure I wrote a subnet calculator iRule a while ago and will post it if you think it would be helpful to solve your requirements.