Thanks a lot for all the advise and help, finally managed to fix it.   Apparently turned out that the ISP in this case (Aussie Broadband) uses CG-NAT (https://www.aussiebroadband.com.au/support/knowledge-base/nbn/cg-nat/). Got on a call with them and opted out of CG-NAT and everything came on track.  ... View more

@Raj66  I see the WAN1 IP and Public IP as 180.X.X.X whereas the IP on the WAN interface is different. Please see the attached screenshot.     ... View more

In google it shows my ip as 180.x.x.x and not 100.x.x.x.   I am also able to ping 180.x.x.x ip from internet. ... View more

The hostname resolves to 180.x.x.x IP and I am able to reach it from outside.   Still, I do not see any icmp packets hitting the internet interface when I do a packet capture. ... View more

I am getting error 789 on windows clients and I have followed the troubleshooting steps. However, that didn't yield anything.   When I look at Uplink for my MX, I see a public IP and a WAN IP and both are different. Public IP is 180.x.x.x whereas the WAN IP is 100.x.x.x. I can ping the public IP from other hosts, but cannot ping the WAN IP. When I do a packet capture with a continuous ping to 180.x.x.x IP address, I do not see any traffic coming in to my MX even though the ping is successful. The ping to 100.x.x.x anyways fails and is not logged in the pcap.   I tried to capture all the icmp traffic with continuous ping to both the ip's running from a PC sitting on internet via 4G/LTE. the only ICMP traffic that I could see was requests being sent to 8.8.8.8 and replies received from it.         ... View more

The D-Link router is in bridge mode and is not getting any WAN IP. The MX is getting public IP.    @rhbirkelund in your case, seems like your MX is getting private IP allocated by ISPs router. ... View more

The DLink us in bridge mode already. I believe it is not blocking anything as the firewall would be completely transparent in bridge mode. Is there any other configuration that needs to be done on it? ... View more