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Pete_A
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Sep 04, 2025
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BIG-IP methods to Fix the “421 Misdirected Request” Error

For those of us that are using the BIG-IP as a reverse proxy to front our internal websites to the world, the recent update to Apache has slapped a big "misdirected request" error across our shop windows.

The fix is that apache is looking for the SNI headers (that's different from the HTTP headers I originally was working with).  The solution to this, for us anyway, was published ages ago in the thread: Serverside SNI injection iRule | DevCentral

Drop that in your iRule and the world starts working again.

Peace, Love and chocolate biscuits all round.

2 Replies

  • Thanks for dropping this use-case / solution pairing Pete_A​.
    Happy to hear that Kai_Wilke​'s codeshare still has legs.

    (I'll further drop the link you provided in a comment associated with you and mark as solution - if you disagree for some reason let me know.)