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Cisco ASA Series CLI Configuration Guide
Chapter 1 Configuring Management Access
Configuring ICMP Access
Configuring ICMP Access
By default, you can send ICMP packets to any ASA interface using either IPv4 or IPv6. This section tells
how to limit ICMP management access to the ASA. You can protect the ASA from attacks by limiting
the addresses of hosts and networks that are allowed to have ICMP access to the ASA.
Note
For allowing ICMP traffic through the ASA, see
Chapter 1, “Configuring Access Rules.”
This section includes the following topics:
•
Information About ICMP Access, page 1-10
•
Licensing Requirements for ICMP Access, page 1-10
•
Guidelines and Limitations, page 1-11
•
•
Configuring ICMP Access, page 1-12
Information About ICMP Access
ICMP in IPv6 functions the same as ICMP in IPv4. ICMPv6 generates error messages, such as ICMP
destination unreachable messages and informational messages like ICMP echo request and reply
messages. Additionally ICMP packets in IPv6 are used in the IPv6 neighbor discovery process and path
MTU discovery.
We recommend that you always grant permission for the ICMP unreachable message type (type 3).
Denying ICMP unreachable messages disables ICMP path MTU discovery, which can halt IPsec and
PPTP traffic. See RFC 1195 and RFC 1435 for details about path MTU discovery.
If you configure ICMP rules, then the ASA uses a first match to the ICMP traffic followed by an implicit
deny all entry. That is, if the first matched entry is a permit entry, the ICMP packet continues to be
processed. If the first matched entry is a deny entry or an entry is not matched, the ASA discards the
ICMP packet and generates a syslog message. An exception is when an ICMP rule is not configured; in
that case, a permit statement is assumed.
Licensing Requirements for ICMP Access
The following table shows the licensing requirements for this feature:
Model
License Requirement
All models
Base License.
Model
License Requirement
All models
Base License.
Содержание 5505 - ASA Firewall Edition Bundle
Страница 28: ...Glossary GL 24 Cisco ASA Series CLI Configuration Guide ...
Страница 61: ...P A R T 1 Getting Started with the ASA ...
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Страница 218: ...1 56 Cisco ASA Series CLI Configuration Guide Chapter 1 Managing Feature Licenses Feature History for Licensing ...
Страница 219: ...P A R T 2 Configuring High Availability and Scalability ...
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Страница 358: ...1 22 Cisco ASA Series CLI Configuration Guide Chapter 1 Information About Failover Failover Messages ...
Страница 403: ...P A R T 2 Configuring Interfaces ...
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Страница 499: ...P A R T 2 Configuring Basic Settings ...
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Страница 533: ...P A R T 2 Configuring Objects and Access Lists ...
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Страница 601: ...P A R T 2 Configuring IP Routing ...
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Страница 680: ...1 48 Cisco ASA Series CLI Configuration Guide Chapter 1 Configuring OSPF Feature History for OSPF ...
Страница 745: ...P A R T 2 Configuring Network Address Translation ...
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Страница 845: ...P A R T 2 Configuring AAA Servers and the Local Database ...
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Страница 981: ...P A R T 2 Configuring Access Control ...
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Страница 994: ...1 12 Cisco ASA Series CLI Configuration Guide Chapter 1 Configuring Access Rules Feature History for Access Rules ...
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Страница 1054: ...1 26 Cisco ASA Series CLI Configuration Guide Chapter 1 Configuring AAA Rules for Network Access Feature History for AAA Rules ...
Страница 1060: ...1 6 Cisco ASA Series CLI Configuration Guide Chapter 1 Configuring Web Cache Services Using WCCP Feature History for WCCP ...
Страница 1061: ...P A R T 2 Configuring Service Policies Using the Modular Policy Framework ...
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Страница 1093: ...P A R T 2 Configuring Application Inspection ...
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Страница 1333: ...P A R T 2 Configuring Connection Settings and QoS ...
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Страница 1379: ...P A R T 2 Configuring Advanced Network Protection ...
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Страница 1474: ...1 18 Cisco ASA Series CLI Configuration Guide Chapter 1 Configuring Filtering Services Monitoring Filtering Statistics ...
Страница 1475: ...P A R T 2 Configuring Modules ...
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Страница 1548: ...1 20 Cisco ASA Series CLI Configuration Guide Chapter 1 Configuring the ASA CSC Module Feature History for the CSC SSM ...
Страница 1549: ...P A R T 2 Configuring VPN ...
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Страница 1796: ...1 6 Cisco ASA Series CLI Configuration Guide Chapter 1 Configuring the PPPoE Client Using Related Commands ...
Страница 1965: ...P A R T 2 Configuring Logging SNMP and Smart Call Home ...
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Страница 2002: ...1 14 Cisco ASA Series CLI Configuration Guide Chapter 1 Configuring NetFlow Secure Event Logging NSEL Feature History for NSEL ...
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Страница 2059: ...P A R T 2 System Administration ...
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