A network administrator notices that remote access VPN users are not reachable from inside the network.
It is determined that routing is configured correctly; however, return traffic is entering the firewall but not leaving it.
What is the reason for this issue?
Click on the arrows to vote for the correct answer
A. B. C. D.D.
Based on the given scenario, remote access VPN users are not reachable from inside the network. It is verified that the routing is set up correctly, but the return traffic is entering the firewall but not leaving it. This issue indicates a problem with Network Address Translation (NAT) configuration on the firewall.
NAT is a process that maps public IP addresses to private IP addresses or vice versa. The firewall NAT configuration can cause issues when it is not correctly configured, which leads to traffic not being able to reach its destination. In the given scenario, the issue is with the NAT configuration for the VPN users.
Option A suggests that a manual NAT exemption rule does not exist at the top of the NAT table. NAT exemption rules exempt specific traffic from NAT translation. If a NAT exemption rule is not correctly configured, it can cause issues with VPN users accessing resources inside the network. However, this is not the case with the given scenario because VPN users can reach the firewall.
Option B states that an external NAT IP address is not configured. An external NAT IP address is used to map the public IP address of the firewall to an internal IP address. If an external NAT IP address is not configured, VPN users cannot access resources inside the network. However, this is not the case in the given scenario because VPN users can reach the firewall.
Option C suggests that an external NAT IP address is configured to match the wrong interface. NAT configuration requires mapping an external IP address to an internal IP address. If the external NAT IP address is configured on the wrong interface, traffic cannot reach the destination. This is a possible cause of the issue in the given scenario.
Option D indicates that an object NAT exemption rule does not exist at the top of the NAT table. Object NAT is a feature that allows NAT to be configured using object-based rules. If an object NAT exemption rule is not correctly configured, it can cause issues with VPN users accessing resources inside the network. However, this is not the case with the given scenario because VPN users can reach the firewall.
Therefore, the most likely reason for the issue in the given scenario is that an external NAT IP address is configured to match the wrong interface, which is option C.