We have an issue in which some of our public IPs will not work from outside. We have a couple of subnets/29. We allow traffic via access rules and they point to internal servers (nat to nat). So I requested an ARP table from our ISP router. The table shows that the non working IPs have a differect MAC address than the working IPs. Our ISP blames our equipment (CIsco ASA 5510) for this. I spoke to Cisco support. They looked at our configuration, and tested it. They say our configuration is correct and the ISP's equipment is doing it.
| IPS | MAC address |
|---|
| *.*.*.5 | *.*.4cd8 |
| *.*.*.4 | *.*.4cd8 |
| *.*.*.3 | *.*.4cd8 |
| *.*.*.2. | *.*.4cd8 |
| *.*.*.204 | *.*.4cd8 |
| *.*.*.205 | *.*.4cd9 |
As you can see above, the IP ending in 205 has a different MAC address ending in 4cd9. It should end
in 4cd8. This seems to happened randomly with all IPs. Like if I restart the ASA. Some of the IPs will not work, and will show a different MAC address.We then have to wait a couple of hrs for them to start work again.
Has anybody seen this before?
