NoNAT8 public IP facing devices not allowing port 22 and 443

[404NotFound]

I have a BT Business Hub installed and a 5 IP block behind the router. I have a simple Cisco router behind it and I can ping the Cisco router on it’s dedicated IP from the internet.

However, I cannot reach it on ssh / ssl.

This should be simple. What am I missing?!

[404NotFound]

It seems that despite it making absolutely no sense at all, you have to put a port forward in. In my mind that configuration would apply only to the current public Ip of the router to LAN devices behind it.

[fguk]

For what you are thinking should happen, you need to put the BT Business Hub into Modem Mode, and configure the Cisco (never heard them called simple before!) to handle the clever stuff, this way the BT Business Hub does no firewalling and you don't need to do any port forwards.

[rachelgomez123]

IP conflicts raised by DHCP servers
DHCP servers are responsible for automatically assigning IP address configurations to devices, referred to as IP leasing, for enabling network connectivity. They maintain a log of the lease information mapping the IP address to the MAC address of the device currently accessing it. Any error or slips in these records may result in an IP address conflict in the network.

Case 1: Server lease information
When the IP address range of a subnet is managed by more than one DHCP server, it's important to ensure that the IP-MAC lease information in all the DHCP servers within the subnet are consistent. Inconsistency with the MAC address retrieved from two DHCP servers' lease information indicates an IP address conflict in the network.

Case 2: Server scope overlap
When more than one DHCP server manages the IP address range of a subnet, address scope overlap may occur between DHCP servers, resulting in IP address conflicts.

Solution:
To start resolving IP address conflict, check the MAC address. If the MAC address associated with the conflicting IP address is that of a network device or host, release its DHCP lease by configuring a static IP address, adjust the scopes of the DHCP servers to avoid overlapping, and then configure the device or host to use a dynamically allocated IP address to connect with the network.

If the MAC address associated with the conflicting IP address is that of a switch port, then block the port temporarily. Adjust the scope of the DHCP servers to avoid overlap, then unblock the switch port.

IP conflicts between DHCP server and IP allocations
Reserving IP addresses allows you to keep aside a particular IP in your address space to a specific host or network device. These reserved IPs are configured with the MAC address of the device. When a DHCP server allocates this IP address to a different network device, then the reservation violation results in IP address conflicts.

Solution:
If the MAC address associated with the conflicting IP address is that of a network device or host, release its current IP address and manually configure the device with an available IP address.
If the MAC address associated with the conflicting IP address is connected to a switch port, then block the switch port temporarily. Release the current IP address of that MAC, manually configure the device with an available IP address, and unblock the switch port.
IP conflicts between IP reservation and IP allocation
Case 1: IP reservation and static IP allocation
When a reserved IP address is statically allocated to a different network device, then the reservation violation results in IP address conflicts.

Solution:
If the MAC address associated with the conflicting IP address is that of a network device or host, release its current IP address and manually configure the device with an available IP address.
If the MAC address associated with the conflicting IP address is connected to a switch port, then block the switch port temporarily. Release the current IP address of that MAC, manually configure the device with an available IP address, and unblock the switch port.
Case 2: IP reservation and DHCP server logs
Reserved IPs are usually associated with the MAC address for which they are reserved in the IP address management system. IP address conflicts occur when there is a difference in the MAC addressees from DHCP leases with reserved MAC addresses tracked by the IP address management system.

Solution:
Check if the conflicting MAC has been assigned a static IP address. If yes, configure the MAC to obtain the IP address dynamically from the DHCP servers.
Inspect the DHCP server logs for any discrepancies.
If the MAC address associated with the conflicting IP address is connected to a switch port, then block the switch port temporarily. Release the current IP address of that MAC, manually configure the device with an available IP address, and unblock the switch port.

Regards,

Rachel Gomez