PAT with 2 providers
Let's push back from the previous publication of Cisco and 2 providers and consider a small problem that many people face when implementing PAT (Port address translation).
In the PAT classic, the Cisco router looks like this:
But when we have 2 providers, both channels work, everything should be symmetrical. If logically, it should be like this:
But it was not there, with the introduction of the last 2 lines, the first 2 are "forgotten" :(
')
With our version with two providers, you need to specify not the interface, but its address, i.e. like this:
In the PAT classic, the Cisco router looks like this:
ip nat inside source static tcp 10.10.10.254 25 interface FastEthernet0/0.12 25
ip nat inside source static tcp 10.10.10.254 110 interface FastEthernet0/0.12 110But when we have 2 providers, both channels work, everything should be symmetrical. If logically, it should be like this:
ip nat inside source static tcp 10.10.10.254 25 interface FastEthernet0/0.12 25
ip nat inside source static tcp 10.10.10.254 110 interface FastEthernet0/0.12 110
ip nat inside source static tcp 10.10.10.254 25 interface FastEthernet0/0.14 25
ip nat inside source static tcp 10.10.10.254 110 interface FastEthernet0/0.14 110But it was not there, with the introduction of the last 2 lines, the first 2 are "forgotten" :(
')
With our version with two providers, you need to specify not the interface, but its address, i.e. like this:
ip nat inside source static tcp 10.10.10.254 25 164.122.12.9 25
ip nat inside source static tcp 10.10.10.254 110 164.122.12.9 110
ip nat inside source static tcp 10.10.10.254 25 122.164.8.17 25
ip nat inside source static tcp 10.10.10.254 110 122.164.8.17 110Source: https://habr.com/ru/post/70832/
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