3 ms·
Mutilevel NAT is a hell of a lot harder to troubleshoot than some extra address bits.
by throwaway2048 9y ago
Mutilevel NAT is a hell of a lot harder to troubleshoot than some extra address bits.
- ra1n85 9y agoWhy would you use multilevel NAT? That sounds like design sadness.
- belorn 9y agoYou can very easy end up with multilevel nat. The last mile (ie a apartment complex) can have one and then the customer router is the second. But that assumes that the ISP has addresses to spare. If not, we have the three layers of nat. ISP->apartment complex->customer router->all customer devices. And then we have intermediates, like ISP->municipal->apartment complex->customer router->customer devices. Now we have four layers of nat. In the really worse case, ISP are split up into multiple ones, and you can get carrier grade NAT in the form of ISP->ISP->municipal->apartment complex->customer router->customer devices. Five layers of nat and up. Multilevel NAT is a form of sadness that NAT never was designed to do.
- zkms 9y agoNAT is also expensive to operate at the scale and reliability that large network operators need. If stateful NAT middleboxes go down, everything goes down -- it's a point of failure that's hard to route around! Also there's the issue that you'll end up having multiple devices with the same RFC1918 addresses, which is an immense pain in the arse to deal with.