Companies using public IP space owned by others for internal routing

Phil Bedard bedard.phil at
Tue Dec 19 05:18:20 CST 2017

I’m pretty sure Comcast, along with most other MSOs in NA, use squat space for various endpoints because they have run out of public and private IPv4 space.   Everyone obviously wants to get to all IPv6 but there are millions of end devices and other gear they speak to which do not support it.  For the most part I think they try to re-use space and use the transition space when they can, but some deployed squat space before that came about or it’s simply not enough.  


On 12/18/17, 3:36 PM, "NANOG on behalf of Mark Andrews" <nanog-bounces at on behalf of marka at> wrote:

    Companies like COMCAST did. They manage the modems over IPv6. 
    They also supported DS-Lite’s development as a transition mechanism so they wouldn’t have to run IPv4 to their customers.  They wanted to be able to go IPv6 only. That meant having IPv4 as a service available. 
    Mark Andrews
    > On 19 Dec 2017, at 06:34, Harald Koch <chk at> wrote:
    >> On 17 December 2017 at 17:48, Tom Carter <m1enrage at> wrote:
    >> RFC1918 isn't big enough to cover all use cases. Think about a large
    >> internet service providers. If you have ten million customers,
    >> would be enough to number modems, but what happens when you need to number
    >> video set top boxes and voice end points? I don't think anyone goes out and
    >> says "Lets go use someone else's space, because I don't want to use this
    >> perfectly good private space".
    > :cough:
    > They could use IPv6. I mean, if the mobile phone companies can figure it
    > out, surely an ISP can...
    > -- 
    > Harald

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