[ Contents] [ Prev] [ Next] [ Index] [ Report an Error]

Example: Defining a Custom Internet Control Message Protocol Application

JUNOS software with enhanced services supports Internet Control Message Protocol (ICMP)—as well as several ICMP messages—as predefined or custom applications. When configuring a custom ICMP application, you must define a type and code.

Before You Begin
Establish basic connectivity. (See the Getting Started Guide for your device.) For background information, read: Understanding the ICMP Predefined Policy Application Understanding Custom Policy Applications Security Policy Applications

There are different message types within ICMP. For example:

type 0 = Echo Request message
- type 3 = Destination Unreachable message
  
  Note: For more information about ICMP types and codes, refer to RFC 792, Internet Control Message Protocol.

An ICMP message type can also have a message code. The code provides more specific information about the message, as shown in Table 37.

Table 37: Message Descriptions

Message Type	Message Code
5 = Redirect	0 = Redirect datagram for the network (or subnet)
	1 = Redirect datagram for the host
	2 = Redirect datagram for the type of application and network
	3 = Redirect datagram for the type of application and host

11 = Time Exceeded Codes	0 =Time to live exceeded in transit
	1 = Fragment reassembly time exceeded

JUNOS software with enhanced services supports any type or code within the 0—255 range.

To define a Custom Internet Control Message Protocol application (ICMP) as the transport protocol, use either J-Web or the CLI configuration editor.

In this example, you define a custom application named “ host-unreachable” using ICMP as the transport protocol. The type is 3 (for destination unreachable) and the code is 1 (for host unreachable). You set the timeout value at 4 minutes.

This topic covers:

[ Contents] [ Prev] [ Next] [ Index] [ Report an Error]