Comcast + PF Sense + internet

  • New to PF Sense… ;D

    I’m using Comcast as my ISP and am having problems getting out to the internet.

    Coaxial cable to Linksys Cable Modem > Cat6 to Dell GX240 nic card > out of second nic to a Cisco 2950 switch ( > out of switch to computers

    Here is what I’ve done those far…

    I’ve followed the directions on the website for setting up the WAN using the Comcast static IP address given me, Subnet Mask and Gateway. I have my Comcast provided DNS IP’s enter in the Primary DNS Server and Secondary DNS Server from the General Information page.

    In the configure WAN interface (I have it as Static)

    I’m using the Spoof option for the MAC Address to Spoof my WAN interface
    MTU 1500

    I’m using for LAN

    Set my Admin Password

    Setup DHCP ( through

    Tested all computer’s connect and they are getting DHCP supplied

    Firewall is wide-open no rules applied.

    But when I try to go out to the internet I get “Page cannot be displayed” and can’t ping outside the LAN.

    So is this because Comcast needs the MAC address of the nic card connected to my Cable Modem?

    I’ve been reading on the forum and looking through pages and pages of documents all week. Since there is so much information out there that it is difficult to know what to look for, some things fit my situation but don’t conclude with an answer.

    I'm excited to learn PF Sense and would like to wrap my head around how to resolve this.

    If anyone can point me to a forum post you might think can help or have a solution I am happy to follow the directions.

    Thank you

  • Goto Status/Interface in the webgui, what does WAN interface display?. Does it have an external adress?

  • @DeCex:

    Goto Status/Interface in the webgui, what does WAN interface display?. Does it have an external adress?

    My WAN does show a WAN address but it's the wrong one… I found that Comcast has dropped my static IP address so I'm on the phone with them trying to get it back.

    I will try again once i get this resolved.

    Thank you

  • comcast gives out ip's based on your mac address
    when you change your router, your mac address is different so you have a different ip.  My ip was the same for years until i changed my mac address and i can change my ip any time i want by changing the mac address

  • wonslung, Comcast does do that if you have DHCP. shredfestival says he has a static IP.

    I've found you sometimes need to power down the comcast modem for about 30 seconds and then reconnect it. For me, it happened when I had my laptop connected to the modem to test the static IP worked and then I plugged it into the router and the modem still was looking for the MAC of my laptop. Powering it down clears that.

  • I can't speak to using a static IP, but I set my DHCP-based one up recently with a similar box and Comcast. (Except with a Linksys 8-port switch, not a Catalyst.  ;))

    The advice about rebooting the cable modem is dead-on. It really didn't make sense to me that it would be necessary, but it was.

    Another bit: I think I had to turn off the "Block private networks" option on the WAN. It may be unnecessary, but turning it off seemed to cure things for me. My cable modem does have an embedded webserver on, sitting on the WAN side, but I'm not sure that should matter. Try it and see if it helps, maybe, even though it seems silly to allow internal IPs to come in via the WAN.

  • yah, i know it's for dhcp, i was just throwing it out there.

    as far as disabling the "block private networks"
    that's a bad idea on the wan side….just my personal opinion....unless you really want your friends and neighbors to have access to your lan..
    maybe it's just me...
    it should be workable without that being turned off

    the reason you have to reset the modem is because of how those comcast modems are setup...they DO give out ip's based on hardware address.i know lots of people with "static ip" who have had to call comcast to get them to fix it..i guess they don't think people will be changing hardware....either that or some of the newer modems don't work like they should........when you change your mac address you have to reboot them, or they will not get an ip.

    at least that's how it is where i live

  • Try this one (resetmodem connection);

    1. Unplug power from modem.
    2. Unplug internet cable from modem.
    3. Plug in the powercable to modem (this will make your router start searching for its host and renew IP, and when that dont work router will get a adress which is good). Keep power up for about 1min

    4. Unplug powercable again
    5. Reboot pfSense box while you plug in both internet cable and powercable to the modem again.
    7. This will make modem goes on with pfSense rebooting and it will start IP renewal after reboot completion. Hopefulle you get a new working WAN IP adress for your box.


  • I have the same problem with pfsense and Comcast. I have to reboot my modem, usually works. If not sometimes reassigning the WLAN/LANS works. Best of luck.

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