It is possible to drop or accept specific packet transmit over edge network interface by rules. Rules can be specify by (-R rule_str) multiple times.
rule_str format: src_ip/len:[b_port,e_port],dst_ip/len:[s_port,e_port],TCP+/-,UDP+/-,ICMP+/-
ip/len indicate a cidr block, len can be ignore, means single ip (not cidr block) will be use in filter rule.
+,- after TCP,UDP,ICMP proto type indicate allow or drop packet of that proto. if any of above three proto missed, the rule will not take effect for that proto.
Ports range [s_port,e_port] can be instead by single port number. If not specify, [0,65535] will be used. Ports range include start_port and end_port.
examples:
192.168.1.5/32:[0,65535],192.168.0.0/24:[8081,65535],TCP-,UDP-,ICMP+
192.168.1.5:[0,65535],192.168.0.0/24:8000,ICMP+
192.168.1.5,192.168.0.7,TCP-,UDP-,ICMP- // packets by all proto of all ports from 192.158.1.5 to any ports of 192.168.0.7 will be dropped.
-R rule_str can be used multiple times to add multiple rules. Each -R rule_str add one rule. for example:
edge -c xxxx -k xxxx -a 192.168.100.5 -l xxx.xxx.xxx.xxx:1234 -r -R 192.168.1.5/32:[0,65535],192.168.0.0/24:[8081,65535],TCP-,UDP-,ICMP+ -R 192.168.1.5:[0,65535],192.168.0.0/24:8000,ICMP+ -R 192.168.1.5,192.168.0.7,TCP-
If multiple rules matching packet's ips and ports, the rule with smaller cidr block(smaller address space) will be selected. That means rules with larger len value has higher priority.
Actually, current implementation will add the len of src cidr and dst cidr of each matched rules as priority value, the rule with largest priority value will take effect.
Packets that cannot match any rule will be accepted by default. Users can add rules to block traffics.
This behavior can be change by add the rule : 0.0.0.0/0:[0,65535],0.0.0.0/0:[0,65535],TCP-,UDP-,ICMP-. Then all traffic will be dropped, users need add rules to allow traffics.
for example, -R 0.0.0.0/0,0.0.0.0/0,TCP-,UDP-,ICMP- -R 192.168.100.0/24,192.168.100.0/24,ICMP+ dropped all traffic, except ICMP traffics inside 192.168.100.0/24.
More complex behavior can be set with the feature of Matching Rules Priority.