Re: Mixing and Matching DHCP and static IPs
On Tue, Dec 26, 2017 at 02:50:44PM -0000, Dan Purgert wrote:
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> Pascal Hambourg wrote:
> > Le 26/12/2017 à 12:33, Dan Purgert a écrit :
> >> [...]
> >> Sounds like perhaps the airstation is blocking client devices from
> >> talking to "bogus" network addresses. This is generally a feature of
> >> consumer gear to stop you from trying to ask the internet for
> >> information about a RFC1918 address (as they are private / not routable
> >> on the internet).
> >
> > What do you mean by "ask the internet for information about a RFC1918
> > address" ? Sending an IP packet is not asking the internet for any
> > information.
>
> No, but if you don't know how to get somewhere (e.g. 192.168.1.0/24 from
> 192.168.11.0/24), you "ask" your gateway for assistance in getting the
> packet to its intended destination.
>
> Now, since RFC1918 space is not routable on the internet, and consumer
> gear is meant to be "easy", some assumptions are made - such that "no,
> they'll never want to use this to talk to an upstream RFC1918 network,
> so we can safely block it and keep them from asking ISP gateways for
> networks that don't actually exist".
>
> This doesn't cause any problems in the setup for "getting to the
> internet" since the destination IP address is not RFC1918.
This is a fascinating sub-thread of the discussion. What I think you are
saying is that, as consumer gear, the AirStation is assuming that if it
is asked to route to a "private" IP address, it essentially refuses,
because that can't be right. I think the BUT here, though, is that I can
ssh from a machine on the inner network (connected to a LAN port of the
AirStation) to the firewall at the outermost edge of my network (that
is, from 192.168.11.x to 192.168.1.1) and that works. From what you are
saying, it shouldn't -- UNLESS, the AirStation makes an exception
specifically for 192.168.1.1 because that is what it has been told its
default gateway is.
Mark
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