Logging requested URI on a 404 redirect rule

I might suggest you try removing the debug cruft and just try this:

 
 when HTTP_REQUEST { 
    set log_uri [HTTP::uri] 
 } 
 when HTTP_RESPONSE { 
    if { [HTTP::status] eq "404" } { 
       HTTP::redirect "http:://10.10.10.1" 
       log "404 error $log_uri - redirected to 10.10.8.106" 
    } 
 } 
 

You do not need to supply the local0. in v9 (this was fixed). The default facility.level is local0.info (you can still specify it if you want to though). If you continue to have trouble then I would suggest you try bracketing the variable with {}, as in ${log_uri}. This is how you deal with embedding a variable in the middle of another word.

For example:

"mybigfatgreek$log_uriwedding" will not work, it will print that string literally. However, if you say "mybigfatgreek${log_uri}wedding" it will work just fine.

Hope any of this helps you debug through your problem.