Specifications

240 Chapter 8. Command Reference
-dp <ICMP type> | <first dest port>[:<last dest port>]
The packet must have a destination port that matches the specified ICMP type or that is within the specified
port range. If only one port is specified, the packet must have that destination port. If no destination port is
specified, the filter matches any destination port in the range 0:0xffff.
-tcp syn|ack|noflag|rst
If the IP packet is a TCP packet, the filter matches the packet only if the packet flag settings are as specified.
If no -tcp option is specified for the filter, flag settings are not checked.
Note: You may specify more than one -tcp option for the IP filter.
The syn, ack, and noflag settings work together as follows:
- Specify -tcp syn if the TCP SYN flag must be set.
- Specify -tcp ack if the TCP ACK flag must be set.
- Specify -tcp noflag if neither the SYN flag nor the ACK flag can be set.
For example, for the IP filter to match the initiation of a TCP connection, specify -tcp syn. The filter will
match TCP packets that have the TCP SYN flag set but not the TCP ACK flag set. For the filter to match the
response to initiation of a TCP connection, specify -tcp syn and -tcp ack. The filter will match only TCP
packets with both the TCP SYN and TCP ACK flags set.
The -tcp rst setting is independent of the others; if you specify -tcp rst for the filter, the filter matches every
TCP packet with the TCP RESET flag set, regardless of the other flag settings. For example, for the filter to
match packets for ÒestablishedÓ connections, you would specify both -tcp rst and -tcp ack so that the filter is
applied to every TCP packet that has either the RESET flag or the ACK flag set.
The following parameters request additional filter options.
-b
This option requests that this filter be compared twice with each packet. The first time the source filter
information is matched against the source information in the IP packet and the destination filter information is
matched against the destination information in the IP packet. The second time the source filter information is
matched against the destination information in the IP packet and the destination filter information is matched
against the source information in the IP packet.
-c <count of times rule used>
This option requests a counter for this filter. If specified, a count is kept of how many IP packets have
matched this filter since the router was rebooted. To see the current count for a filter, use the eth ip filter list
command. To clear a counter, use the eth ip filter clear command.
-ipsec <IPSec record name>
Use this option when the action specified is inipsec or outipsec. It specifies the IPSec Security Association
that uses the filter.
-q or -v
Specify one of these options to determine when watch messages are sent for this filter. The messages are sent
to the console serial port (and to any Syslog servers; see page 153).
If neither -q or -v are specified for the filter, and an eth ip filter watch on command is entered for the
interface, a message is sent each time this filter causes a packet to be dropped or rejected.
If -q (quiet) is specified, no messages are printed for this filter, even if the filter causes a packet to be dropped
or rejected.