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Forum Discussion

SRM's avatar
SRM
Icon for Altocumulus rankAltocumulus
Dec 18, 2025

Illegal Metacharacter in Parameter Name in Json Data

Dears, 
Can someone tell what is the issue here as the BIG IP is reporting the illegal metacharacter "#" in parameter name but the highlighted part of the violation doesnt contain metacharacter # in the first place and the parameter which BIG IP displayed in the highlighted part is actually not a parameter. I believe the issue is with the BIG IP only. Any suggestions here, please? I think issue is that BIG IP is not paring the Json payload properly

application delivery
cloud
security

3 Replies

  • Juergen_Mang's avatar
    Juergen_Mang
    Icon for MVP rankMVP
    Dec 18, 2025

    If "Parse as parameters" is checked, each JSON key is treated as parameter name. You can disable this checkbox or configure the parameter name metachars accordingly.

  • SRM's avatar
    SRM
    Icon for Altocumulus rankAltocumulus
    Dec 19, 2025

    Dear Juergen,

    Thanks for your response. Yes, it’s true that “Parse as parameters” is checked, but my question is why the highlighted part is considered a single parameter when it contains almost 12 to 13 JSON keys and their values

  • NicolasDupin's avatar
    NicolasDupin
    Icon for Nimbostratus rankNimbostratus
    Dec 19, 2025

    How is your json profile used ?

    I will be curious to see your "Header-Based Content Profiles" tab.

    It might be that your profile is just, not applied (and then doesn't parse the json correctly) ?

    I would also be interresting to see your violation with the detailed tab (you only displayed the request data). But it is strange that it states "#"