- Configuring NAT for IP Address Conservation
- Using Application Level Gateways with NAT
- Configuring NAT for High Availability
- Scalability for Stateful NAT
- Integrating NAT with MPLS VPNs
- Configuring Hosted NAT Traversal for Session Border Controller
- User Defined Source Port Ranges for PAT
- FPG Endpoint Agnostic Port Allocation
- NAT Optimized SIP Media Path Without SDP
- NAT Optimized SIP Media Path with SDP
- Monitoring and Maintaining NAT
FPG Endpoint Agnostic Port Allocation
When the Endpoint Agnostic Port Allocation feature is configured, an entry is added to the Symmetric Port Database. If the entry is already available, the port listed in the Symmetric Port Database is used and the packet is sent. This feature is only required if you need to configure NAT with pool overload or interface overload. Endpoint Agnostic Port Allocation is also known as Symmetric Port Allocation.
Finding Feature Information
Your software release may not support all the features documented in this module. For the latest feature information and caveats, see the release notes for your platform and software release. To find information about the features documented in this module, and to see a list of the releases in which each feature is supported, see the Feature Information Table at the end of this document.
Use Cisco Feature Navigator to find information about platform support and Cisco software image support. To access Cisco Feature Navigator, go to www.cisco.com/go/cfn. An account on Cisco.com is not required.
Information About Endpoint Agnostic Port Allocation
When a packet is being transmitted, the Symmetric Port Database is checked to see if the requested port is already allocated. If it has been allocated, it is checked if the source computer entry in the database matches the computer requesting the port. If this is true, the port listed in the Symmetric Port Database is used and the packet is sent.
If the computers do not match or if the requested port is not in the Symmetric Port Database, the feature continues checks to the NAT Port database for an entry matching the requested port. If no entry is found, this means that the port is available. A new entry is added to the NAT Port database, and to the existing NAT database, allocating the port to the requesting computer, and the packet is sent.
If no matching entry in the NAT Port database is found, it means that the port is busy, or otherwise unavailable. The next available port is found, which is allocated to the requesting computer. An entry is added to the NAT Port database with the requesting computer and the available port. An entry is added to the Symmetric Port database, with the requesting computer, the allocated port and the requested port and the packet is sent.
This feature is only required if you need to configure NAT with pool overload or interface overload. This feature is not applicable for other NAT configurations.
How to Configure Endpoint Agnostic Port Allocation
Configuring Endpoint Agnostic Port Allocation
Perform this task to configure NAT to support the Endpoint Agnostic Port Allocation feature.
 Note |
This feature must be enabled by the user. It should be enabled before NAT is enabled. If it is enabled later, it will not translate the previously established connection. When this feature is disabled, it will not be seen in the output of the show running-configcommand. > |
DETAILED STEPS
Verifying Endpoint Agnostic Port Support
To verify the Endpoint Agnostic Port Support feature, use the following command.
DETAILED STEPS
|
Example:
Router# show ip nat translations
NAT Symmetric Port Database: 1 entries
public ipaddr:port [tableid] | port# [refcount][syscount] | localaddr:localport [flags]
172.18.192.69:1024 [0] | 1025 [1] [0] | 172.18.192.69:1024 [0]
|
Configuration Examples for Endpoint Agnostic Port Allocation
Configuring Endpoint Allocation Example
interface Ethernet0/0 ip nat inside exit access list 1 permit 172.18.192.0.0.0.255 ip nat inside source list 1 interface Ethernet0/0 ip nat service enable-sym-port end
Additional References
Related Documents
| Related Topic |
Document Title |
|---|---|
| NAT configuration tasks |
"Configuring NAT for IP Address Conservation" module |
| NAT maintenance |
"Monitoring and Maintaining NAT" module |
| NAT commands: complete command syntax, command mode, command history, usage guidelines, and examples |
Cisco IOS IP Addressing Services Command Reference |
Standards
| Standard |
Title |
|---|---|
| No new or modified standards are supported by this feature, and support for existing standards has not been modified by this feature. |
_ |
MIBs
| MIB |
MIBs Link |
|---|---|
| No new or modified MIBs are supported by this feature, and support for existing MIBs has not been modified by this feature. |
To locate and download MIBs for selected platforms, Cisco IOS releases, and feature sets, use Cisco MIB Locator found at the following URL: |
RFCs
| RFC |
Title |
|---|---|
| No new or modified RFCs are supported by this feature, and support for existing RFCs has not been modified by this feature. |
_ |
Technical Assistance
| Description |
Link |
|---|---|
| The Cisco Support and Documentation website provides online resources to download documentation, software, and tools. Use these resources to install and configure the software and to troubleshoot and resolve technical issues with Cisco products and technologies. Access to most tools on the Cisco Support and Documentation website requires a Cisco.com user ID and password. |
Feature Information for Endpoint Agnostic Port Allocation
The following table provides release information about the feature or features described in this module. This table lists only the software release that introduced support for a given feature in a given software release train. Unless noted otherwise, subsequent releases of that software release train also support that feature.
Use Cisco Feature Navigator to find information about platform support and Cisco software image support. To access Cisco Feature Navigator, go to www.cisco.com/go/cfn. An account on Cisco.com is not required.
| Table 1 | Feature Information for NAT Endpoint Agnostic Port Allocation |
| Feature Name |
Releases |
Feature Information |
|---|---|---|
| FPG: Endpoint Agnostic Port Allocation |
12.4(24)T |
This feature was introduced. |
Cisco and the Cisco logo are trademarks or registered trademarks of Cisco and/or its affiliates in the U.S. and other countries. To view a list of Cisco trademarks, go to this URL: www.cisco.com/go/trademarks. Third-party trademarks mentioned are the property of their respective owners. The use of the word partner does not imply a partnership relationship between Cisco and any other company. (1110R)
Any Internet Protocol (IP) addresses and phone numbers used in this document are not intended to be actual addresses and phone numbers. Any examples, command display output, network topology diagrams, and other figures included in the document are shown for illustrative purposes only. Any use of actual IP addresses or phone numbers in illustrative content is unintentional and coincidental.
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