| Current Path : /usr/share/examples/ipfilter/ |
FreeBSD hs32.drive.ne.jp 9.1-RELEASE FreeBSD 9.1-RELEASE #1: Wed Jan 14 12:18:08 JST 2015 root@hs32.drive.ne.jp:/sys/amd64/compile/hs32 amd64 |
| Current File : //usr/share/examples/ipfilter/BASIC_2.FW |
#!/sbin/ipf -f - # # SAMPLE: PERMISSIVE FILTER RULES # # THIS EXAMPLE IS WRITTEN FOR IP FILTER 3.3 # # ppp0 - (external) PPP connection to ISP, address a.b.c.d/32 # # ed0 - (internal) network interface, address w.x.y.z/32 # # This file contains the basic rules needed to construct a firewall for the # above situation. # #------------------------------------------------------- # *Nasty* packets we don't want to allow near us at all! # short packets which are packets fragmented too short to be real. block in log quick all with short #------------------------------------------------------- # Group setup. # ============ # By default, block and log everything. This maybe too much logging # (especially for ed0) and needs to be further refined. # block in log on ppp0 all head 100 block out log on ppp0 all head 150 block in log on ed0 from w.x.y.z/24 to any head 200 block out log on ed0 all head 250 #------------------------------------------------------- # Invalid Internet packets. # ========================= # # Deny reserved addresses. # block in log quick from 10.0.0.0/8 to any group 100 block in log quick from 192.168.0.0/16 to any group 100 block in log quick from 172.16.0.0/12 to any group 100 # # Prevent IP spoofing. # block in log quick from a.b.c.d/24 to any group 100 # #------------------------------------------------------- # Localhost packets. # ================== # packets going in/out of network interfaces that aren't on the loopback # interface should *NOT* exist. block in log quick from 127.0.0.0/8 to any group 100 block in log quick from any to 127.0.0.0/8 group 100 block in log quick from 127.0.0.0/8 to any group 200 block in log quick from any to 127.0.0.0/8 group 200 # And of course, make sure the loopback allows packets to traverse it. pass in quick on lo0 all pass out quick on lo0 all #------------------------------------------------------- # Allow any communication between the inside network and the outside only. # # Allow all outgoing connections (SSH, TELNET, FTP, WWW, gopher, etc) # pass in log quick proto tcp all flags S/SA keep state group 200 # # Support all UDP `connections' initiated from inside. # # Allow ping out # pass in log quick proto icmp all keep state group 200 #------------------------------------------------------- # Log these: # ========== # * return RST packets for invalid SYN packets to help the other end close block return-rst in log proto tcp from any to any flags S/SA group 100 # * return ICMP error packets for invalid UDP packets block return-icmp(net-unr) in proto udp all group 100