Configuração de NAT para EIP (Elastic IP) no Asterisk

Question

Ao executar o Asterisk no Amazon EC2 com um EIP, quais são as configurações do NAT para o Asterisk?

[general]
nat=yes
externip=xxx.yyy.zzz.vvv
localnet=192.168.0.0/255.255.0.0 ; RFC 1918 addresses
localnet=10.0.0.0/255.0.0.0      ; Also RFC1918
localnet=172.16.0.0/12           ; Another RFC1918 with CIDR notation
localnet=169.254.0.0/255.255.0.0 ; Zero conf local network

Aparentemente, o EIC usa o NAT :

If your EC2 instance is in a private subnet in your VPC, then it can use your NAT to make outbound connections. The outside world would see it's IP address as your NAT's IP address, but the NAT's IP address would never "be" the Public IP address of the instance.

Visão geral de como o EIP funciona :

Before going into an example, let's review how the Elastic IPs work:

...

Remember that each instance has an internal IP address and an external (public) one, which is translated to the internal one. If two external IPs were translated to the same internal IP then inbound packets would arrive fine, but sorting out outgoing packets (i.e. determining which external IP address to assign to outgoing packets) would be very difficult. Hence, the limitation of a single external IP address per instance at any given point in time.

wikipedia (para minha referência):

Elastic IP addresses Amazon Elastic IP

Amazon's elastic IP address feature is similar to static IP address in traditional data centers, with one key difference. A user can programmatically map an elastic IP address to any virtual machine instance without a network administrator's help and without having to wait for DNS to propagate the binding. In this sense an Elastic IP Address belongs to the account and not to a virtual machine instance. It exists until it is explicitly removed, and remains associated with the account even while it is associated with no instance.

Descendo para as porcas e parafusos, no contexto do SIP e do Asterisk :

1.3. Different types of NATs and firewalls.

There are several ways UDP might be handled by a specific NAT or firewall implementations, these are categorized into:

1.3.1 Full Cone NAT

A full cone NAT is one where all requests from the same internal IP address and port are mapped to the same external IP address and port. Furthermore, any external host can send a packet to the internal host, by sending a packet to the mapped external address.

1.3.2 Restricted Cone:

A restricted cone NAT is one where all requests from the same internal IP address and port are mapped to the same external IP address and port. Unlike a full cone NAT, an external host (with IP address X) can send a packet to the internal host only if the internal host had previously sent a packet to IP address X.

1.3.3 Port Restricted Cone:

A port restricted cone NAT is like a restricted cone NAT, but the restriction includes port numbers.

Specifically, an external host can send a packet, with source IP address X and source port P, to the internal host only if the internal host had previously sent a packet to IP address X and port P.

1.3.4 Symmetric Nat:

A symmetric NAT is one where all requests from the same internal IP address and port, to a specific destination IP address and port, are mapped to the same external IP address and port. If the same host sends a packet with the same source address and port, but to a different destination, a different mapping is used. Furthermore, only the external host that receives a packet can send a UDP packet back to the internal host.

Parece que o EIC usa NAT "full cone". Quais seriam as configurações do Asterisk para NAT, então?

    

Answer 1

Externip deve ser definido como ip externo

Localnet definido para a rede local (verifique usando ifconfig).

Claro

nat=comedia,rport

(nat = sim não funciona nas versões modernas).