Hello. I'm configuring freebsd firewall and have such situation:

51000 pipe tablearg ip from not table(17) to table(20) out xmit ng*
51010 pipe tablearg ip from table(21) to not table(17) in recv ng*
51020 pipe tablearg ip from any to table(18) out xmit ng*
51030 pipe tablearg ip from table(19) to any in recv ng*

tables 18,19,20,21 have client ip addresses and pipe numbers table 17 list of networks.

rules 51020 and 51030 work fine but what is going at 51000 and 51010 ? How to determine firewall to take pipe number from tables 20 and 21 - not from 17 ?