• Serial Console on pfSense ASA

    Rhea Rae • 6 days ago • 0 comments

    The ASA 5525-X can run pfSense while retaining usable appliance-style console access through the original RJ45 console port at 9600 baud.


    pfSense serial console works through the ASA 5525-X front RJ45 console port after enabling serial console in pfSense and setting baud rate to 9600.

    Tera Term / serial settings:

    Baud: 9600

    Data: 8 bit

    Parity: none

    Stop bits: 1

    Flow control: none

  • Turning a Cisco ASA 5525-X Into a Real pfSense Firewall

    Rhea Rae • 7 days ago • 0 comments

    This side project started with a simple goal: I wanted a machine that could run pfSense and give me more control over my home lab network.

    What I ended up with was much more interesting.

    The Cisco ASA 5525-X is normally a locked-down enterprise firewall appliance. It is powerful hardware, but it is also heavily tied to Cisco’s software, licensing, and feature model. My unit still has the original Cisco ASA software intact on its original storage, but I was able to install pfSense onto a separate 128 GB internal drive that was not being used for my current setup.

    That means the project is not just a wipe-and-reinstall. It is a reversible dual-boot style setup where the original Cisco environment remains available, while pfSense runs from its own drive.

    Hardware Used

    The system is a Cisco ASA 5525-X appliance with:

    Intel Xeon X3430 quad-core CPU

    8 GB RAM

    128 GB internal drive used for pfSense

    Multiple onboard Intel gigabit Ethernet interfaces

    Original Cisco ASA storage still preserved

    VGA header access for direct setup

    BIOS-level boot control

    Possible PCIe expansion/riser present on the board

    This was one of the most surprising parts of the project. Under the Cisco branding, this appliance is very much a normal x86 computer. It is not useful as a gaming machine or desktop system, but for routing, firewalling, VLANs, network monitoring, and lab use, it is extremely well suited.

    What Was Done

    The first major step was getting direct video access to the ASA motherboard. The unit has an internal VGA header, so I worked out the correct orientation and was able to access the BIOS directly.

    From there, I changed the boot order so the system could boot pfSense from the 128 GB internal drive while leaving the original Cisco ASA storage in place as a fallback.

    pfSense installed successfully and booted on the ASA hardware. Once the system was configured, I was able to put the chassis back together, remove the temporary VGA jumper setup, and manage the firewall through the pfSense web GUI.

    That was a major turning point. At that point the ASA stopped feeling like a locked appliance and started acting like a real open firewall platform.

    Network Setup So Far

    The current home lab network includes:

    Cisco Catalyst 3850 switch

    SonicWall NSA 2650 firewall currently still in production

    Cisco ASA 5525-X now running pfSense as a lab firewall

    VLAN 10 lab network

    Trusted LAN / management network

    UniFi UAP-AC-PRO access point

    Pi-hole DNS filtering

    Windows-based UniFi Network application

    The Catalyst 3850 has been configured with VLAN separation. The SonicWall currently still acts as the main gateway, while VLAN 10 is being used as the lab network. The ASA/pfSense setup can now be tested inside that lab network before replacing or taking over duties from the SonicWall.

    This makes the migration safer. Instead of ripping out the existing firewall all at once, the new pfSense firewall can be built, tested, documented, backed up, and compared before becoming the main firewall.

    Important Accomplishments

    The ASA 5525-X successfully boots pfSense.

    The original Cisco ASA operating system was preserved.

    The pfSense install uses a separate 128 GB internal drive.

    The system can be managed through the pfSense web GUI.

    The Cisco Catalyst 3850 has VLAN segmentation working.

    VLAN 10 exists as a dedicated lab network.

    The SonicWall still provides the current production gateway while pfSense is tested.

    The setup is repeatable and documented.

    The ASA hardware is no longer limited to Cisco’s licensing model while running pfSense.

    Why This Matters

    The biggest win here is freedom.

    The ASA 5525-X was originally designed to run Cisco ASA software, with Cisco licensing controlling what features are available. Under pfSense, the same physical hardware becomes much more flexible. The Ethernet ports, storage, CPU, and RAM can be used by an open firewall platform instead of being limited by the original...

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  • pfSense

    Rhea Rae • 05/31/2026 at 19:03 • 0 comments

  • ASA pfSense Pin Out

    Rhea Rae • 05/31/2026 at 14:43 • 0 comments

  • ASA 5525-X Bios

    Rhea Rae • 05/31/2026 at 14:06 • 0 comments

    F2 to enter 
    Setup boot order

    Disable ROMMON Boot

    UFS and GPT needs to be selected not ZFS in install prompt pfsense

    1st boot: USB HDD

    2nd boot: Your HDD

    3rd boot: eUSB-HDD: UNIGEN 

  • ASA 5525-X Pin diagram-adapter

    Rhea Rae • 05/31/2026 at 13:50 • 0 comments


    pccables.com VGA Port HD15F Adapter to IDC16 Part#07129 PC -07129

    Pin 16 on ASA 5525-X is unpopulated. 

    Red stripe on adapter cable aligns with pin 1 side of board connector.

  • VGA Header ASA 5525-X

    Rhea Rae • 05/31/2026 at 13:40 • 0 comments

  • Rack

    Rhea Rae • 05/23/2026 at 18:35 • 0 comments