ICMP Module

The module icmp is used for sending ICMP Echo Request messages.

This module is useful only for xlat. Use it via the following expansion:

The module will "ping" the given IP address. If that IP address responds with an ICMP Echo Reply, then the result of the expansion will be yes. If that IP address does not respond within the timeout, then the result of the expansion will be no.

The IP address does not have to be a fixed string. It can be another expansion, such as:

Capabilities and Permissions

On Linux, you may need to do:

In order for the icmp module to bind to a "raw" socket.

Configuration Settings

interface: Which interface to use for sending ICMP packets.

By default, packets are sent via the normal routing table.

Specifying an interface forces the packets to be sent via that particular interface.

src_ipaddr: Source address for ICMP messages.

timeout: How long to wait for the reply.

Default is 1 seconds, which should be plenty for nearly anything. Range is 0.1s to 10s.

You are strongly encouraged to NOT increase this value. In fact, you are much better off decreasing it to a lower value. Doing so will improve network stability and responsiveness.

Ping for IPv4

Copy of the icmp module, as it may be easier to remember ping than icmp.

A version for ICMPv6

Default Configuration

#	`%icmp(192.0.2.1)`
#	`%icmp:(%{NAS-IP-Address})`
#	$ setcap cap_net_raw+ep ${bindir}/radiusd
icmp {
#	interface = eth0
	src_ipaddr = *
	timeout = 1s
}
icmp ping {
	timeout = 1s
	src_ipaddr = *
}
icmp ping6 {
	timeout = 1s
	src_ipaddr = ::
}