I compiled and used 3.2 version of ipfilter on 1.21 NetBSD. There were 2 internal nets and everything was O.K. After instaling 1.31 I used old configuration files for ipf, and the problem started. It seems to work only partly: for example, what is for me very imprtant, I cant do an ftp connections from computers in internal nets - ftp works only on gateway to real network. Can anyone help me in resolving this problem? After few days of workink i have no new concepts, what can i do more. 
Thanks in advance  Stanley