converting decimal to hex in a ksh script

first one should read:
   echo 10.10.20.21 | awk -F. '{print $1*256*256*256)+($2*256*256)+($3*256)+$4;}
sorry.

Thank you!
It works, with a little change in syntax, but for an IP of 10.10.20.21, I get an answer 168433e+08
How can I format the naswer to give the whole number?

awk -F. '{printf "%d",($1*256*256*256)+($2*256*256)+($3*256)+$4;}'
 awk -F. '{printf "%08x",($1*256*256*256)+($2*256*256)+($3*256)+$4;}'
But this may fail for 128.10.20.21
perl -ne 'printf"%08x",unpack"N",pack"C*",split/\./'

echo 128.10.20.21 | awk -F. '{printf "%12.12d",($1*256*256*256)+($2*256*256)+($3*256)+$4;}'

works for me, but depending on your OS leading chars are blanks or zeros

You can do the whole job without using awk or perl:

#!/bin/ksh
IFSsave=$IFS
typeset -i a b c d     # declare fields to be integer
IFS='.'
echo 10.10.20.21 | read a b c d
IFS=$IFSsave

echo $(((a<<24)+(b<<16)+(c<<8)+d))
# if a>127 the result will be a negative number
exit