Setting An Icmp Acl - Nortel 2360 Configuration Manual

414 Configuring and managing security ACLs

Setting an ICMP ACL

With the following command, you can use security ACLs to set Internet Control Message Protocol (ICMP) parameters
for the ping command:
set security acl ip acl-name {permit [cos cos] | deny} icmp {source-ip-addr mask | any}
{destination-ip-addr mask | any} [type icmp-type] [code icmp-code]
[[precedence precedence] [tos tos] | [dscp codepoint]]
[before editbuffer-index | modify editbuffer-index] [hits]
An ICMP ACL can filter packets by source and destination IP address, TOS level, precedence, ICMP type, and ICMP
code. For example, the following command permits all ICMP packets coming from 192.168.1.3 and going to
192.168.1.4 that also meet the following conditions:
• ICMP type is 11 (Time Exceeded).
• ICMP code is 0 (Time to Live Exceeded).
• Type-of-service level is 12 (minimum delay plus maximum throughput).
• Precedence is 7 (network control).
WSS# set security acl ip acl-3 permit icmp 192.168.1.3 0.0.0.0 192.168.1.4 0.0.0.0 type 11 code
0 precedence 7 tos 12 before 1 hits
The before 1 portion of the ACE places it before any others in the ACL, so it has precedence over any later ACEs for
any parameter settings that are met.
For more information about changing the order of ACEs or otherwise modifying security ACLs, see
security ACL" (page 426). For information about TOS and precedence levels, see the
2300 Series Command Line
ICMP includes many messages that are identified by a type field. Some also have a code within that type.
some common ICMP types and codes. For more information, see www.iana.org/assignments/icmp-parameters.
ICMP Message Type (Number)
Echo Reply (0)
Destination Unreachable (3)
Source Quench (4)
Redirect (5)
Echo (8)
NN47250-500 (320657-F Version 02.01)
Reference. For CoS details, see
Table 3: Common ICMP message types and codes
"Class of Service" (page
ICMP Message Code (Number)
None
• Network Unreachable (0)
• Host Unreachable (1)
• Protocol Unreachable (2)
• Port Unreachable (3)
• Fragmentation Needed (4)
• Source Route Failed (5)
None
• Network Redirect (0)
• Host Redirect (1)
• Type of Service (TOS) and Network Redirect (2)
• TOS and Host Redirect (3)
None
"Modifying a
Nortel WLAN Security Switch
412).
Table 3 lists