Do Firewalls in Access Mode Need OSPF Configuration?

Newbie404178 Lv1Posted Jun-20-2025 11:42

Topology Overview:
- Two routers (R1 and R2) connected to two firewalls (FW-1 and FW-2) in HA mode.
- Two FS switches (SW-1 and SW-2) are stacked via 100G ports.
- Each switch connects to its respective firewall.
- The NGAF firewalls are currently configured in Access Mode (not doing Layer 3 routing).
- OSPF is running on the routers and potentially on the switches.

My Question:
Do I need to configure OSPF on the firewalls even if they are only in access (transparent) mode ?

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No, you do not need to configure OSPF on the firewalls if they are operating in Access Mode (Transparent Mode).
In Access (Transparent) Mode the NGAF firewalls operate at Layer 2 and they do not participate in routing or maintain a routing table. They simply bridge traffic between interfaces while applying security policies. Since OSPF is a Layer 3 protocol it is not relevant or functional on a firewall in transparent mode.
Is this answer helpful?
Prosi Lv3Posted Jun-25-2025 11:35
  
No you do not need to configure OSPF on the firewalls
J sain Lv1Posted Jun-25-2025 03:46
  
No, firewalls in access mode generally do not require OSPF configuration. Access mode firewalls typically handle traffic based on pre-defined rules and policies, and don't require dynamic routing protocols like OSPF for routing decisions. OSPF is typically used in routed firewall mode, where the firewall acts as a router, participating in dynamic routing with other routers in the network.
Syed Majid Lv1Posted Jun-24-2025 13:41
  
No, firewalls in access mode generally do not require OSPF configuration. Access mode firewalls typically handle traffic based on pre-defined rules and policies, and don't require dynamic routing protocols like OSPF for routing decisions. OSPF is typically used in routed firewall mode, where the firewall acts as a router, participating in dynamic routing with other routers in the network.
SMHussain Lv1Posted Jun-24-2025 13:40
  
No, firewalls in access mode generally do not require OSPF configuration. Access mode firewalls typically handle traffic based on pre-defined rules and policies, and don't require dynamic routing protocols like OSPF for routing decisions. OSPF is typically used in routed firewall mode, where the firewall acts as a router, participating in dynamic routing with other routers in the network.
mantasha Lv2Posted Jun-23-2025 14:54
  
No, if the firewalls are in Access Mode (sometimes called Transparent Mode), you do not need to set up OSPF on them.  Justification:  In transparent mode, a firewall does the following:  functions at Layer 2 (similar to a bridge).  lacks IP ports on transit lines and does not take part in Layer 3 routing.  allows data to flow between interfaces without being routed.  Because it lacks IP interfaces in the data stream, it is unable to establish OSPF (or any other dynamic routing protocol) adjacencies.  What You Must Do Instead:  If they are using Layer 3 routing, OSPF should be set up on the switches (SW-1 and SW-2) and routers (R1 and R2).  All that the firewalls will do is act as a traffic bridge between the switches and routers.  Make sure that the appropriate VLANs are transmitted.The required traffic, including multicast for OSPF if applicable, is permitted via firewall rules.  Correct forwarding and learning are occurring in the MAC and ARP tables.  When Would Firewalls Require OSPF?  Firewalls can only take part in OSPF if they are in Layer 3 routing mode and terminate subnets or interfaces.
AR Lv2Posted Jun-21-2025 17:08
  
No, you do not need to configure OSPF on the firewalls if they are operating in Access Mode (also known as Transparent Mode).

Explanation:
When a firewall is in transparent mode, it:

Operates at Layer 2 (like a bridge).

Does not participate in Layer 3 routing (no IP interfaces on transit links).

Passes traffic between interfaces without routing it.

Cannot form OSPF (or any dynamic routing protocol) adjacencies because it doesn't have IP interfaces in the data path.

What You Should Ensure Instead:
OSPF should be configured on the routers (R1 and R2) and the switches (SW-1 and SW-2) if they are doing Layer 3 routing.

The firewalls will simply bridge traffic between the routers and switches.

Ensure that:

Proper VLANs are passed through.

Firewall rules allow the necessary traffic (including multicast for OSPF if relevant).

The MAC and ARP tables are learning and forwarding correctly.

When Would You Need OSPF on Firewalls?
Only if the firewalls are in routing mode (Layer 3) and terminate subnets or interfaces—then they can participate in OSPF.

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