Document ID: 17657
Contents
Introduction
Prerequisites
Requirements
Affected Products
Affected Versions
More Information
Related Information
Introduction
In certain cases, it might be beneficial to have more than one external address for the internal users to be translated to.
Prerequisites
Requirements
There are no specific requirements for this document.
Affected Products
1200i, 1220i, 1250i, 1270i, 2600i, 2900i, 2200R, 2220R, 2250R, 2270R, 3500R, 3800R, 4000S, VSR-2, and VSR-8 IntraGuard
Affected Versions
All versions
More Information
Even without any NAT Mapping, you might want to put in a second external address for your internal addresses to be translated into. One address can handle hundreds of web access translations, but only one ping packet at a time. If you have a continuous ping that goes out through the NAT device to the Internet, then no one else is able to ping the Internet. This is caused because the ICMP protocol does not use a port number and the router is unable to determine where multiple pings should be returned to if it allowed more than one to NAT. Therefore, it only allows one ping out at a time per external address.
This is normally not a problem, but some mail and other software programs use pings to determine if a device is still available. If one ping is already using the NAT, then the second device is not able to ping. This can cause problems with those software packages that rely on ping connectivity for them to work. In cases like these, put in additional external IP addresses so that the NAT router is able to handle more than one ping at a time. This is the only case where multiple external ranges use other than the first IP address.
Related Information
| Updated: May 03, 2004 | Document ID: 17657 |