Memo to self, may help other folks.

When debugging a complex process that is highly sensitive to initial conditions, you must start from the same initial conditions each iteration.

Practical example: the Linux Netfilter firewalling system is a thing of amazing power and flexibility. It will also happily hide information that you don't ask for. `iptables -L -n -v` lists only the MAIN firewall table -- if you have done anything with NAT, you must also examine the NAT table, and remember to flush it separately.

Memo to self, may help other folks.

When debugging a complex process that is highly sensitive to initial conditions, you must start from the same initial conditions each iteration.

Practical example: the Linux Netfilter firewalling system is a thing of amazing power and flexibility. It will also happily hide information that you don't ask for. `iptables -L -n -v` lists only the MAIN firewall table -- if you have done anything with NAT, you must also examine the NAT table, and remember to flush it separately.