O endereço de WAN que você tem está na faixa reservada para CGN (NAT de categoria de operadora, RFC 6598, prefixo IPv4 reservado por IANA para Espaço de Endereçamento Compartilhado . Esse intervalo é 100.64.0.0/10 e significa que seu ISP está atribuindo a você o que é essencialmente um endereço privado e também está fazendo NAT. A maioria dos ISPs nem usa esse intervalo atribuído pela IANA para isso, eles apenas usam o espaço de endereço RFC 1918 regular. Seu encaminhamento de porta não funciona porque você não está encaminhando o NAT do ISP, e o ISP não encaminhará a porta para você, pois isso impediria que todos os outros clientes naquele NAT pudessem usar essa porta.
Os RIRs esgotaram os endereços IPv4 para serem atribuídos aos ISPs, portanto, os ISPs estão se voltando para a CGN para atribuir endereços IPv4 não públicos a clientes residenciais, economizando seu precioso pool de endereços IP públicos para clientes corporativos dispostos a pagar um prêmio para endereços IPv4 públicos.
A maioria dos ISPs residenciais tem cláusulas nos contratos de clientes que proíbem que você execute um servidor da rede residencial para a Internet, portanto eles não se importam se a CGN impedir isso para clientes residenciais.
Do RFC:
1. Introduction
IPv4 address space is nearly exhausted. However, ISPs must continue to support IPv4 growth until IPv6 is fully deployed. To that end, many ISPs will deploy a Carrier-Grade NAT (CGN) device, such as that described in [RFC6264]. Because CGNs are used on networks where public address space is expected, and currently available private address space causes operational issues when used in this context, ISPs require a new IPv4 /10 address block. This address block will be called the "Shared Address Space" and will be used to number the interfaces that connect CGN devices to Customer Premises Equipment (CPE).
Shared Address Space is similar to [RFC1918] private address space in that it is not globally routable address space and can be used by multiple pieces of equipment. However, Shared Address Space has limitations in its use that the current [RFC1918] private address space does not have. In particular, Shared Address Space can only be used in Service Provider networks or on routing equipment that is able to do address translation across router interfaces when the addresses are identical on two different interfaces.
This document requests the allocation of an IPv4 /10 address block to be used as Shared Address Space. In conversations with many ISPs, a /10 is the smallest block that will allow them to deploy CGNs on a regional basis without requiring nested CGNs. For instance, as described in [ISP-SHARED-ADDR], a /10 is sufficient to service Points of Presence in the Tokyo area.
This document details the allocation of an additional special-use
IPv4 address block and updates [RFC5735].
O RFC também lista alguns dos problemas causados pelo CGN:
5.2. Empirical Data
The primary motivation for the allocation of Shared Address Space is as address space for CGNs; the use and impact of CGNs has been previously described in [RFC6269] and[NAT444-IMPACTS]. Some of the services adversely impacted by CGNs are as follows:
Console gaming -- some games fail when two subscribers using the same outside public IPv4 address try to connect to each other.
Video streaming -- performance is impacted when using one of several popular video-streaming technologies to deliver multiple video streams to users behind particular CPE routers.
Peer-to-peer -- some peer-to-peer applications cannot seed content due to the inability to open incoming ports through the CGN. Likewise, some SIP client implementations cannot receive incoming calls unless they first initiate outgoing traffic or open an incoming port through the CGN using the Port Control Protocol (PCP) [PCP-BASE] or a similar mechanism.
Geo-location -- geo-location systems identify the location of the CGN server, not the end host.
Simultaneous logins -- some websites (particularly banking and social-networking websites) restrict the number of simultaneous logins per outside public IPv4 address.
6to4 -- 6to4 requires globally reachable addresses and will not work in networks that employ addresses with limited topological span, such as those employing CGNs.