Do any wireless routers do DHCP relay besides Airports?

Discussion in 'Apple' started by paris2venice@gmail.com, Apr 19, 2012.

  1. Guest

    I have a faculty member who, for some illogical reason, refuses to buy an Apple Airport Express or Extreme simply because he thinks I am biased in favor of Apple. Of course, I am not. I'd rather that any wireless router could do this but many are not capable of passing the DHCP request on to your real DHCP server so that you get a real IP address instead of a private IP.I am required to do this by the campus so I simply conforming to campus policy.

    Does anyone know of any current models of wireless routers that do this?

    Just for anyone interested, this is how it is done in Airport Utility:

    Internet icon > Connection Sharing: Off (Bridge Mode)

    Thanks for any help.
    , Apr 19, 2012
    #1
    1. Advertising

  2. nospam Guest

    In article
    <33280880.1213.1334871787546.JavaMail.geo-discussion-forums@vbbfj25>,
    <> wrote:

    > I have a faculty member who, for some illogical reason, refuses to buy an
    > Apple Airport Express or Extreme simply because he thinks I am biased in
    > favor of Apple. Of course, I am not. I'd rather that any wireless router
    > could do this but many are not capable of passing the DHCP request on to your
    > real DHCP server so that you get a real IP address instead of a private IP.
    > I am required to do this by the campus so I simply conforming to campus
    > policy.
    >
    > Does anyone know of any current models of wireless routers that do this?


    all of them.

    bridge mode is one way but the easiest is connect it lan-lan. make
    absolutely sure the dhcp server in the second router is off.
    nospam, Apr 19, 2012
    #2
    1. Advertising

  3. Guest

    On Thursday, April 19, 2012 3:08:21 PM UTC-7, nospam wrote:
    > In article
    > <33280880.1213.1334871787546.JavaMail.geo-discussion-forums@vbbfj25>,
    >
    > wrote:
    >
    > > I have a faculty member who, for some illogical reason, refuses to buy an
    > > Apple Airport Express or Extreme simply because he thinks I am biased in
    > > favor of Apple. Of course, I am not. I'd rather that any wireless router
    > > could do this but many are not capable of passing the DHCP request on to your
    > > real DHCP server so that you get a real IP address instead of a private IP.
    > > I am required to do this by the campus so I simply conforming to campus
    > > policy.
    > >
    > > Does anyone know of any current models of wireless routers that do this?

    >
    > all of them.
    >
    > bridge mode is one way but the easiest is connect it lan-lan. make
    > absolutely sure the dhcp server in the second router is off.


    What does connect it "lan-lan" mean? And what do you mean, "second router"? Where the "first router" is my subnet's gateway?
    , Apr 19, 2012
    #3
  4. nospam Guest

    In article
    <14407241.1825.1334874269963.JavaMail.geo-discussion-forums@vbbdy9>,
    <> wrote:

    > > > I have a faculty member who, for some illogical reason, refuses to buy an
    > > > Apple Airport Express or Extreme simply because he thinks I am biased in
    > > > favor of Apple. Of course, I am not. I'd rather that any wireless router
    > > > could do this but many are not capable of passing the DHCP request on to
    > > > your real DHCP server so that you get a real IP address instead of a private
    > > > IP. I am required to do this by the campus so I simply conforming to campus
    > > > policy.
    > > >
    > > > Does anyone know of any current models of wireless routers that do this?

    > >
    > > all of them.
    > >
    > > bridge mode is one way but the easiest is connect it lan-lan. make
    > > absolutely sure the dhcp server in the second router is off.

    >
    > What does connect it "lan-lan" mean?


    routers have a wan port to connect to the cable/dsl modem and one or
    more lan ports for your computers.

    what you want to do is *not* use the wan port, but rather connect one
    of those lan ports to the rest of the network, which connects to the
    lan port of some other router. leave the wan port empty. no bridging or
    nat will take place. as i said, be sure dhcp is off.

    > And what do you mean, "second router"?


    the one you want to buy and connect to your network.

    > Where the "first router" is my subnet's gateway?


    yes. there's something already in place, isn't there?
    nospam, Apr 19, 2012
    #4
  5. JF Mezei Guest

    re: question about second router.

    DHCP works by sending an ethernet broadcast to all devices on the LAN.
    If you have more than one DHCP server on the LAN, then each DHCP server
    will respomd to the request with an offer, and the client then deides
    which of the 2 offers to accept.

    This is why you ony want one DHCP server active on any LAN segment to
    ensure that it is the only one answering DHCP requests and distributing
    IPs from a single IP pool.
    JF Mezei, Apr 20, 2012
    #5
  6. In article
    <33280880.1213.1334871787546.JavaMail.geo-discussion-forums@vbbfj25>,
    wrote:

    > I have a faculty member who, for some illogical reason, refuses to buy an
    > Apple Airport Express or Extreme simply because he thinks I am biased in
    > favor of Apple. Of course, I am not. I'd rather that any wireless router
    > could do this but many are not capable of passing the DHCP request on to your
    > real DHCP server so that you get a real IP address instead of a private IP.
    > I am required to do this by the campus so I simply conforming to campus
    > policy.
    >
    > Does anyone know of any current models of wireless routers that do this?
    >
    > Just for anyone interested, this is how it is done in Airport Utility:
    >
    > Internet icon > Connection Sharing: Off (Bridge Mode)
    >
    > Thanks for any help.


    You're mixing up DHCP and NAT. They're often used together but they can
    be independent.

    DHCP is giving a computer an available address. It can be local or
    public.

    NAT is translating one address and port to another, usually so that
    multiple local addresses can share one public address.

    Bridged mode makes the AP behave like a slow wire. It doesn't perform
    any services beyond establishing the WiFi connection. All respectable
    access points will have this mode.

    DHCP relay allows one DHCP central server to control multiple local
    networks. It's not likely what you want to turn on, but most high-end
    APs support it.
    --
    I will not see posts from Google because I must filter them as spam
    Kevin McMurtrie, Apr 20, 2012
    #6
  7. JF Mezei <> wrote:

    > re: question about second router.
    >
    > DHCP works by sending an ethernet broadcast to all devices on the LAN.
    > If you have more than one DHCP server on the LAN, then each DHCP server
    > will respomd to the request with an offer, and the client then deides
    > which of the 2 offers to accept.
    >
    > This is why you ony want one DHCP server active on any LAN segment to
    > ensure that it is the only one answering DHCP requests and distributing
    > IPs from a single IP pool.


    Aye, the OP simply needs to connect any router to the existing network
    using one of it's LAN ports (not WAN as others also point out) and
    disable DHCP on said router. FYI - many routers handily allow
    configuration of the WAN port so it will behave as a normal LAN port.

    --
    If you're not part of the solution, you're part of the precipitate.
    Jamie Kahn Genet, Apr 20, 2012
    #7
  8. Paul Sture Guest

    On Thu, 19 Apr 2012 23:29:50 -0700, Kevin McMurtrie wrote:

    > In article
    > <33280880.1213.1334871787546.JavaMail.geo-discussion-forums@vbbfj25>,
    > wrote:
    >
    >> I have a faculty member who, for some illogical reason, refuses to buy
    >> an Apple Airport Express or Extreme simply because he thinks I am
    >> biased in favor of Apple. Of course, I am not. I'd rather that any
    >> wireless router could do this but many are not capable of passing the
    >> DHCP request on to your real DHCP server so that you get a real IP
    >> address instead of a private IP. I am required to do this by the campus
    >> so I simply conforming to campus policy.
    >>
    >> Does anyone know of any current models of wireless routers that do
    >> this?
    >>
    >> Just for anyone interested, this is how it is done in Airport Utility:
    >>
    >> Internet icon > Connection Sharing: Off (Bridge Mode)
    >>
    >> Thanks for any help.

    >
    > You're mixing up DHCP and NAT. They're often used together but they can
    > be independent.
    >
    > DHCP is giving a computer an available address. It can be local or
    > public.
    >
    > NAT is translating one address and port to another, usually so that
    > multiple local addresses can share one public address.
    >
    > Bridged mode makes the AP behave like a slow wire. It doesn't perform
    > any services beyond establishing the WiFi connection. All respectable
    > access points will have this mode.
    >
    > DHCP relay allows one DHCP central server to control multiple local
    > networks. It's not likely what you want to turn on, but most high-end
    > APs support it.


    And this is a feature of Windows Server 2008. You can service all DHCP
    request from software, with different ranges for different subnets and so
    on.

    (Sorry for the interruption. Normal OS X service resumes.)



    --
    Paul Sture
    Paul Sture, Apr 20, 2012
    #8
  9. Guest

    On Thursday, April 19, 2012 3:42:06 PM UTC-7, nospam wrote:
    > In article
    > <14407241.1825.1334874269963.JavaMail.geo-discussion-forums@vbbdy9>,
    >
    > wrote:
    >
    > > > > I have a faculty member who, for some illogical reason, refuses to buy an
    > > > > Apple Airport Express or Extreme simply because he thinks I am biased in
    > > > > favor of Apple. Of course, I am not. I'd rather that any wirelessrouter
    > > > > could do this but many are not capable of passing the DHCP request on to
    > > > > your real DHCP server so that you get a real IP address instead of a private
    > > > > IP. I am required to do this by the campus so I simply conforming to campus
    > > > > policy.
    > > > >
    > > > > Does anyone know of any current models of wireless routers that do this?
    > > >
    > > > all of them.
    > > >
    > > > bridge mode is one way but the easiest is connect it lan-lan. make
    > > > absolutely sure the dhcp server in the second router is off.

    > >
    > > What does connect it "lan-lan" mean?

    >
    > routers have a wan port to connect to the cable/dsl modem and one or
    > more lan ports for your computers.
    >
    > what you want to do is *not* use the wan port, but rather connect one
    > of those lan ports to the rest of the network, which connects to the
    > lan port of some other router. leave the wan port empty. no bridging or
    > nat will take place. as i said, be sure dhcp is off.
    >
    > > And what do you mean, "second router"?

    >
    > the one you want to buy and connect to your network.
    >
    > > Where the "first router" is my subnet's gateway?

    >
    > yes. there's something already in place, isn't there?


    Those last two questions were intended to clarify what you meant and nothing else. However, I do have another question. How do I determine the MAC address of the LAN port that I have connected my cat5 cable? I searched my DHCP server's log file for failures (I deny unknown clients) and didn't getanything resembling the WAN port's MAC address.
    , Apr 21, 2012
    #9
  10. Guest

    On Thursday, April 19, 2012 6:46:54 PM UTC-7, JF Mezei wrote:
    > re: question about second router.
    >
    > DHCP works by sending an ethernet broadcast to all devices on the LAN.
    > If you have more than one DHCP server on the LAN, then each DHCP server
    > will respomd to the request with an offer, and the client then deides
    > which of the 2 offers to accept.
    >
    > This is why you ony want one DHCP server active on any LAN segment to
    > ensure that it is the only one answering DHCP requests and distributing
    > IPs from a single IP pool.


    Thanks but you misunderstood my question.
    , Apr 21, 2012
    #10
  11. Guest

    On Thursday, April 19, 2012 11:29:50 PM UTC-7, Kevin McMurtrie wrote:
    > In article
    > <33280880.1213.1334871787546.JavaMail.geo-discussion-forums@vbbfj25>,
    > I wrote:
    >
    > > I have a faculty member who, for some illogical reason, refuses to buy an
    > > Apple Airport Express or Extreme simply because he thinks I am biased in
    > > favor of Apple. Of course, I am not. I'd rather that any wireless router
    > > could do this but many are not capable of passing the DHCP request on to your
    > > real DHCP server so that you get a real IP address instead of a private IP.
    > > I am required to do this by the campus so I simply conforming to campus
    > > policy.
    > >
    > > Does anyone know of any current models of wireless routers that do this?
    > >
    > > Just for anyone interested, this is how it is done in Airport Utility:
    > >
    > > Internet icon > Connection Sharing: Off (Bridge Mode)
    > >
    > > Thanks for any help.

    >
    > You're mixing up DHCP and NAT. They're often used together but they can
    > be independent.
    >
    > DHCP is giving a computer an available address. It can be local or
    > public.
    >
    > NAT is translating one address and port to another, usually so that
    > multiple local addresses can share one public address.
    >
    > Bridged mode makes the AP behave like a slow wire. It doesn't perform
    > any services beyond establishing the WiFi connection. All respectable
    > access points will have this mode.
    >
    > DHCP relay allows one DHCP central server to control multiple local
    > networks. It's not likely what you want to turn on, but most high-end
    > APs support it.


    No. I am not mixed up. I put this network in (several thousand feet of cable in 7 buildings over 20 years ago) -- I do know what DHCP and NAT are. The latter, however, I never use except at home.
    , Apr 21, 2012
    #11
  12. JF Mezei Guest

    wrote:

    > Thanks but you misunderstood my question.



    If you know that DHCP works as an ethernet broadcast then you either
    need to ensure your wireless access point acts as an ethernet bridge
    which passes broadcasts, or is setup as a DHCP relay.


    Because DHCP is an ethernet broadcast, it cannot go further than the
    boundary of your LAN. In the cable world, this means that it goes from
    your cable modem tothe CMTS at the other end and hits the limit of the
    coax LAN.

    the CMTS is configured to act as a DHCP relay. It encapsulates your DHCP
    request and adds some tags to it and then sends it to the known DHCP
    server location.

    The DHCP server gets your request, knows which CMTS serves you and thus
    from whcih subnet it needs to offer you an IP address and also knows
    that it needs to send the answer back to that CMTS (which will then send
    it back to you ).

    So the use of DHCP Relay refers to stuff that is more complex than what
    consumers see and what the average DHCP server is able to handle.
    JF Mezei, Apr 21, 2012
    #12
    1. Advertising

Want to reply to this thread or ask your own question?

It takes just 2 minutes to sign up (and it's free!). Just click the sign up button to choose a username and then you can ask your own questions on the forum.
Similar Threads
  1. Replies:
    4
    Views:
    334
    Barry Watzman
    Nov 10, 2006
  2. Replies:
    0
    Views:
    298
  3. Replies:
    1
    Views:
    370
  4. Joshua Chessman
    Replies:
    0
    Views:
    188
    Joshua Chessman
    Jan 21, 2004
  5. Replies:
    4
    Views:
    371
    Mac Dude
    Jul 27, 2008
Loading...

Share This Page