Re: should request to 192.168.x.x get out of my router to the WAN? - TCP-IP

This is a discussion on Re: should request to 192.168.x.x get out of my router to the WAN? - TCP-IP ; james wrote: > If I type http://192.168.1.1 in my browser and the LAN has no such host, > should the router forward this request out to the WAN? > My home network: > DSL--> dlink router --> zyxel wireless router ...

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Thread: Re: should request to 192.168.x.x get out of my router to the WAN?

  1. Re: should request to 192.168.x.x get out of my router to the WAN?

    james wrote:

    > If I type http://192.168.1.1 in my browser and the LAN has no such host,
    > should the router forward this request out to the WAN?


    > My home network:


    > DSL--> dlink router --> zyxel wireless router


    > I thought that a non routeable address like 192.168.x.x is supposed to
    > stay in the LAN and *never* gets out of the router.


    comp.protocols.tcp-ip added, where this should really go.
    (It is an IP question, not an ethernet question.)

    192.168.x.x should not route on the public Internet, but,
    personally, I would expect a small home router to route it.
    I would be disappointed if it didn't.

    Consider the case of double NAT, which sounds like what you have.

    If a host on the wireless net, which should be a different
    (sub)net from the wired net, wants to address a host on the
    wired net it would need a 192.168.x.y address.

    Note that x and/or y must be different on the two nets.

    Your ISP router should block it pretty early, or at least
    before it gets outside the ISPs network.

    -- glen


  2. Re: should request to 192.168.x.x get out of my router to the WAN?

    In article <8O6dndvaT6iRC0PVnZ2dnUVZ_qzinZ2d@comcast.com>,
    glen herrmannsfeldt wrote:

    > james wrote:
    >
    > > If I type http://192.168.1.1 in my browser and the LAN has no such host,
    > > should the router forward this request out to the WAN?

    >
    > > My home network:

    >
    > > DSL--> dlink router --> zyxel wireless router

    >
    > > I thought that a non routeable address like 192.168.x.x is supposed to
    > > stay in the LAN and *never* gets out of the router.

    >
    > comp.protocols.tcp-ip added, where this should really go.
    > (It is an IP question, not an ethernet question.)
    >
    > 192.168.x.x should not route on the public Internet, but,
    > personally, I would expect a small home router to route it.
    > I would be disappointed if it didn't.


    Correct, since the router has no way of knowing whether the WAN
    interface is connected to the "public Internet" or some other network
    that also uses private IPs.

    So anything that isn't in the subnet assigned to the LAN will be
    forwarded to the WAN.

    --
    Barry Margolin, barmar@alum.mit.edu
    Arlington, MA
    *** PLEASE post questions in newsgroups, not directly to me ***
    *** PLEASE don't copy me on replies, I'll read them in the group ***

  3. Re: should request to 192.168.x.x get out of my router to the WAN?

    >> > If I type http://192.168.1.1 in my browser and the LAN has no such
    >> > host,
    >> > should the router forward this request out to the WAN?

    >>
    >> 192.168.x.x should not route on the public Internet, but,
    >> personally, I would expect a small home router to route it.
    >> I would be disappointed if it didn't.

    >
    > Correct, since the router has no way of knowing whether the WAN
    > interface is connected to the "public Internet" or some other network
    > that also uses private IPs.
    >
    > So anything that isn't in the subnet assigned to the LAN will be
    > forwarded to the WAN.


    Thank you all for correcting my misconception.


  4. Re: should request to 192.168.x.x get out of my router to the WAN?

    Barry Margolin wrote:
    (snip)

    > Correct, since the router has no way of knowing whether the WAN
    > interface is connected to the "public Internet" or some other network
    > that also uses private IPs.


    > So anything that isn't in the subnet assigned to the LAN will be
    > forwarded to the WAN.


    It might be that some router manufacturers get it wrong,
    though, but double NAT should be legal. My home wireless
    net runs double NAT through the wired net, both on
    net 10 subnets.

    It does seem that many home routers will only allow subnets
    down to /24. That is, no more than 254 hosts. I suppose
    that is a reasonable limit for a home network.

    -- glen


  5. Re: should request to 192.168.x.x get out of my router to the WAN?

    glen herrmannsfeldt wrote:
    [snip]
    > It does seem that many home routers will only allow subnets
    > down to /24. That is, no more than 254 hosts. I suppose
    > that is a reasonable limit for a home network.


    Until your fridge needs an IP, your TV, Audio/Video receivers, blu-ray
    players..... and the Rowenta iron!

    It's a matter of time before everyone will have to buy an 6509 switch!



    --

    hsb


    "Somehow I imagined this experience would be more rewarding" Calvin
    ************************************************** ******************
    Due to the volume of email that I receive, I may not be able to
    reply to emails sent to my account. Please post a followup instead.
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  6. Re: should request to 192.168.x.x get out of my router to the WAN?

    Hansang Bae wrote:
    (snip, I wrote)

    >>It does seem that many home routers will only allow subnets
    >>down to /24. That is, no more than 254 hosts. I suppose
    >>that is a reasonable limit for a home network.


    > Until your fridge needs an IP, your TV, Audio/Video receivers, blu-ray
    > players..... and the Rowenta iron!


    Or subnets?

    I am still waiting for the toaster oven with IP.
    (I have seen them with RS232 for biology lab use.)

    For security reasons it is best to have separate subnets
    for wired and wireless nets. That gives two subnets
    already for a house.

    -- glen


  7. Re: should request to 192.168.x.x get out of my router to the WAN?

    In comp.protocols.tcp-ip glen herrmannsfeldt wrote:
    > I am still waiting for the toaster oven with IP.


    I cannot assert that the toasters were directly connected to IP, my
    dimm memory doesn't work well that far back, but in the early days of
    Interop, one of the "staples" of the show flow were SNMP toasters.

    rick jones
    --
    The computing industry isn't as much a game of "Follow The Leader" as
    it is one of "Ring Around the Rosy" or perhaps "Duck Duck Goose."
    - Rick Jones
    these opinions are mine, all mine; HP might not want them anyway...
    feel free to post, OR email to rick.jones2 in hp.com but NOT BOTH...

  8. Re: should request to 192.168.x.x get out of my router to the WAN?

    In article ,
    Rick Jones wrote:

    > In comp.protocols.tcp-ip glen herrmannsfeldt wrote:
    > > I am still waiting for the toaster oven with IP.

    >
    > I cannot assert that the toasters were directly connected to IP, my
    > dimm memory doesn't work well that far back, but in the early days of
    > Interop, one of the "staples" of the show flow were SNMP toasters.
    >


    That's correct. John Romkey (author of SLIP, among other things) did an
    SNMP-managed toaster (1950's retro style) with an embedded
    microprocessor and TCP/IP protocol stack. It used a 10BASE2 coaxial
    cable Ethernet connection to the network. I believe it was demo'ed at
    the 1988 or 1989 InterOp show.


    --
    Rich Seifert Networks and Communications Consulting
    21885 Bear Creek Way
    (408) 395-5700 Los Gatos, CA 95033
    (408) 228-0803 FAX

    Send replies to: usenet at richseifert dot com

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