Thanks for confirming my issue.
I think the libipt_* files are built from the iptables
source not kernel source. I can modprobe ipt_connbytes
kernel module, it is the library that is missing.
I guess what I'd like to see is the latest iptables package
from slackware include support for *all* the iptables kernel
modules available in the recent vanilla kernels.
I could compile iptables libraries myself, sure, but doesn't
this seem like an oversight wrt the iptables package?
How would one go about making this kind of request? An e-mail
to PJV, himself? Does he read ths forum? Slackware.com still
lists this as "our favorite Slackware questions forum".