Question How to Assign ISP given Public IP to Secondary Router?

[Syed289]

Good day fellows,
I wanted to give a wholesome picture of the problem. So, apologies for the long post. I have a problem and the need to solve that problem and if my need can be met without solving the problem that will work too...

Problem
I have two routers the first and main one is ZTE - F670L provided by ISP it has a public IP 182.x.x.x on the wan side. I have set up a secondary router (CISCO-RV320) through a LAN cable between the Lan2 port on the ZTE router to WAN1 of Cisco. Now the Cisco is showing 192.168.x.x ip on wan which is DHCP provided by ZTE. What I want to do is set up the routers in such a way that my secondary router (Cisco) gets public IP 182.x.x.x on its wan side. Is there any way?

Need:
I have a client who will give me access to their server only through the IPSEC gateway to the gateway VPN. And that has to be set up using public IPs at some stage. My ISP-provided router does not have VPN features, so I bought a Cisco RV320 but it does not pick up the public IP I am not sure if I will be able to connect to the IPSEC tunnel.

 

[bill001g]

The NAT issue partially why ipsec is not used as much and things like wireguard and openvpn are much more popular.

Ipsec is always a pain so I have not used it in a while. It is possible to get it to run though nat. There is a special configuration option that allows it to work. It is considered slightly less secure but it is better that running without encryption.

The only way to actually get the IP on the wan port would be to find a way to put the ISP router in bridge mode. Not all ISP allow this.

Note a couple documents that were leaked by snowden years ago talked about the NSA attempt to inject vulnerabilities into IPSEC. No way to know if they have been successful yet or not.

 

[Syed289]

The NAT issue partially why ipsec is not used as much and things like wireguard and openvpn are much more popular.

Ipsec is always a pain so I have not used it in a while. It is possible to get it to run though nat. There is a special configuration option that allows it to work. It is considered slightly less secure but it is better that running without encryption.

The only way to actually get the IP on the wan port would be to find a way to put the ISP router in bridge mode. Not all ISP allow this.

Note a couple documents that were leaked by snowden years ago talked about the NSA attempt to inject vulnerabilities into IPSEC. No way to know if they have been successful yet or not.

Thanks Bill, from your answer I made out that wireguard and openVPN should not cause any problems with the current private i.p on Cisco's wan interface... Is that so?

 

[bill001g]

It is not so much private IP that causes the issue with IPSEC. Both openvpn and wireguard use standard TCP and UDP. IPSEC uses a completely different protocol and you can't "forward" a "protocol". But you can make IPSEC use UDP and UDP can work with port forwarding.
More the question would be does the cisco have support for openvpn or wireguard. That is a rather old router. There are many modern consumer routers that support both openvpn and wireguard.