shorewall-arprules 5 Configuration Files arprules Shorewall ARP rules file /etc/shorewall/arprules IPv4 only. This file was added in Shorewall 4.5.12 and is used to describe low-level rules managed by arptables (8). These rules only affect Address Resolution Protocol (ARP), Reverse Address Resolution Protocol (RARP) and Dynamic Reverse Address Resolution Protocol (DRARP) frames. The columns in the file are as shown below. MAC addresses are specified normally (6 hexadecimal numbers separated by colons). ACTION Describes the action to take when a frame matches the criteria in the other columns. Possible values are: ACCEPT This is the default action if no rules matches a frame; it lets the frame go through. DROP Causes the frame to be dropped. SNAT:ip-address Modifies the source IP address to the specified ip-address. DNAT:ip-address Modifies the destination IP address to the specified ip-address. SMAT:mac-address Modifies the source MAC address to the specified mac-address. DMAT:mac-address Modifies the destination MAC address to the specified mac-address. SNATC:ip-address Like SNAT except that the frame is then passed to the next rule. DNATC:ip-address Like DNAT except that the frame is then passed to the next rule. SMATC:mac-address Like SMAT except that the frame is then passed to the next rule. DMATC:mac-address Like DMAT except that the frame is then passed to the next rule. SOURCE - [interface[:[!]ipaddress[/ipmask][:[!]macaddress[/macmask]]]] Where interface Is an interface defined in shorewall-interfaces(5). ipaddress is an IPv4 address. DNS names are not allowed. ipmask specifies a mask to be applied to ipaddress. macaddress The source MAC address. macmask Mask for MAC address; must be specified as 6 hexadecimal numbers separated by colons. When '!' is specified, the test is inverted. If not specified, matches only frames originating on the firewall itself. Either SOURCE or DEST must be specified. DEST - [interface[:[!]ipaddress[/ipmask][:[!]macaddress[/macmask]]]] Where interface Is an interface defined in shorewall-interfaces(5). ipaddress is an IPv4 address. DNS Names are not allowed. ipmask specifies a mask to be applied to frame addresses. macaddress The destination MAC address. macmask Mask for MAC address; must be specified as 6 hexadecimal numbers separated by colons. When '!' is specified, the test is inverted and the rule matches frames which do not match the specified address/mask. If not specified, matches only frames originating on the firewall itself. If both SOURCE and DEST are specified, then both interfaces must be bridge ports on the same bridge. Either SOURCE or DEST must be specified. OPCODE - [[!]opcode] Optional. Describes the type of frame. Possible opcode values are: 1 ARP Request 2 ARP Reply 3 RARP Request 4 RARP Reply 5 Dynamic RARP Request 6 Dynamic RARP Reply 7 Dynamic RARP Error 8 InARP Request 9 ARP NAK When '!' is specified, the test is inverted and the rule matches frames which do not match the specified opcode. The eth1 interface has both a public IP address and a private address (10.1.10.11/24). When sending ARP requests to 10.1.10.0/24, use the private address as the IP source: #ACTION SOURCE DEST ARP OPCODE SNAT:10.1.10.11 - eth1:10.1.10.0/24 1 /etc/shorewall/arprules shorewall(8)