TCL Error

Using the statement "If" would look like this:

if { [string tolower [HTTP::host]] equals "www.abc.com" or [string tolower [HTTP::host]] equals "abc.com" or [string tolower [HTTP::host]] equals "a.b.c.d" } { 
    HTTP::respond 301 Location "http://wp.abc.com/" 
} 

Replace the "if" statement by "switch", something like this:

switch [string tolower [HTTP::host]] {
    "www.abc.com" -
    "abc.com" -
    "a.b.c.d" { 
        HTTP::respond 301 Location "http://wp.abc.com/" 
    }
} 

https://www.tcl.tk/man/tcl8.4/TclCmd/switch.htm

Hope this helps.