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Muhannad's avatar
Muhannad
Icon for Cirrus rankCirrus
Oct 17, 2022

Rewrite Subdomain

Dears,

I am wondering about an efficient procedure to search and replace a specific Subdomain in the HOST, What i want to achieve is rewrite the HTTP request toward the server side as follows:

Client Request: DIRx.Clust1.Domain.com ----Should be forwarded to server side as follows:--- DIRx.Clust2.Domain.com, Only rewrite the Clust1 to Clust2 in the HOST, noting that the x value is variable DIRx and keep changing so i am unable to achieve the rewrite by simple Rule to replace the whole domain, i want to have a universal rule that can match the DIR# and copy it successfully to the domain when the rewrite happened.

Please can you guide me if there is any useful workaround.

Regards,

Muhannad

application delivery
  • CA_Valli's avatar
    CA_Valli
    Oct 17, 2022

    Code above is case sensitive on HTTP::host match. 

    If you want a case-insensitive match you can run this instead

    when HTTP_REQUEST {
#    log local0. "Client requested host: [HTTP::host]"
  if { [string tolower [HTTP::host]] starts_with "dir" && [string tolower [HTTP::host]] contains "clust1" }{
    HTTP::header replace Host [string map {"clust1" "clust2"}[string tolower [HTTP::host]]]
#        log local0. "Modified host: [HTTP::host]"
  }
}

     

    Oct 17 15:43:07 bigip info tmm7[11345]: Rule /Common/test-iRule <HTTP_REQUEST>: Client requested host: DIR000.Clust1.Domain.com
Oct 17 15:43:07 bigip info tmm7[11345]: Rule /Common/test-iRule <HTTP_REQUEST>: Modified host: dir000.clust2.domain.com
  • CA_Valli's avatar
    CA_Valli
    Icon for MVP rankMVP
    Oct 17, 2022
    when HTTP_REQUEST {
  if { [HTTP::host] starts_with "DIR" && [HTTP::host] contains "Clust1" }{
  HTTP::header replace Host [string map {"Clust1" "Clust2"}[HTTP::host]]
  }
}

     

    Sample execution logs: 

    Oct 17 15:32:37 bigip info tmm[11345]: Rule /Common/test-iRule <HTTP_REQUEST>: Client requested host: DIRx.Clust1.Domain.com
Oct 17 15:32:37 bigip info tmm[11345]: Rule /Common/test-iRule <HTTP_REQUEST>: Modified host: DIRx.Clust2.Domain.com
Oct 17 15:32:41 bigip info tmm6[11345]: Rule /Common/test-iRule <HTTP_REQUEST>: Client requested host: DIRy.Clust1.Domain.com
Oct 17 15:32:41 bigip info tmm6[11345]: Rule /Common/test-iRule <HTTP_REQUEST>: Modified host: DIRy.Clust2.Domain.com
Oct 17 15:32:43 bigip info tmm6[11345]: Rule /Common/test-iRule <HTTP_REQUEST>: Client requested host: DIRz.Clust1.Domain.com
Oct 17 15:32:43 bigip info tmm6[11345]: Rule /Common/test-iRule <HTTP_REQUEST>: Modified host: DIRz.Clust2.Domain.com

     

    • CA_Valli's avatar
      CA_Valli
      Icon for MVP rankMVP
      Oct 17, 2022

      Code above is case sensitive on HTTP::host match. 

      If you want a case-insensitive match you can run this instead

      when HTTP_REQUEST {
#    log local0. "Client requested host: [HTTP::host]"
  if { [string tolower [HTTP::host]] starts_with "dir" && [string tolower [HTTP::host]] contains "clust1" }{
    HTTP::header replace Host [string map {"clust1" "clust2"}[string tolower [HTTP::host]]]
#        log local0. "Modified host: [HTTP::host]"
  }
}

       

      Oct 17 15:43:07 bigip info tmm7[11345]: Rule /Common/test-iRule <HTTP_REQUEST>: Client requested host: DIR000.Clust1.Domain.com
Oct 17 15:43:07 bigip info tmm7[11345]: Rule /Common/test-iRule <HTTP_REQUEST>: Modified host: dir000.clust2.domain.com