Routing for Cogent

  • I am switching my pfSense from a /28 from Centurylink to a /28 from Cogent.

    With Centurylink, it's simple: the first host of my /28 is provided by CL and is my gateway for the remainder of the hosts. All I need to do is assign pfSense an IP and a gateway, and it works! Centurylink Example:
    GW: (provided by CL upstream on a Cisco device)
    Remaining hosts:

    Moving to Cogent, they have assigned my Router a /29 and my clients a /28:
    Connected Address Block:
    Cogent Router port IP/Gateway:
    Customer Router Port IP:

    Cogent Assigned IP Block :

    I'm pretty sure I that if I assign the pfSense WAN an IP of: and a GW of: then my LAN will have access to the internet.

    Question #1 is: How do I use the remaining IP address? Can I simply add Virtual IP/Alias?

    Question #2 is: Can I provision a pfSense with WAN an IP of: and a GW of:, then set up the LAN as and then provision other pfSense(s) on, each with their own LAN?

  • @unsichtbarre #1 yes and #2 yes, not just pfsenses, also hosts with internet services in a dmz, filtered by pf rules as needed.

  • @netblues Thanks!

    If #2, how do I enable generic (forward all traffic) downstream routing to the pfSenses

  • @unsichtbarre You don't. Your isp has routed the /28 behind
    Just put firewall rules, as usual.

    Downstream pfsenses will have 47.33 as default gw. (and nat any traffic behind them)


  • @netblues Awesome!
    I get a few more IPs than I had with CL!

  • @netblues thank you this was very helpful!

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