Very interesting, thanks! I need to look more closely but a quick note: most of the IPAddr methods should probably be inlined to avoid the function call overhead. That might help a bit with the CPU. Robin -- Robin Sommer * Phone +1 (510) 722-6541 * robin at icir.org ICSI/LBNL * Fax +1 (510) 666-2956 * www.icir.org