pppd and ms_dns - PPP

This is a discussion on pppd and ms_dns - PPP ; If I have Linux system with DNS configured (that is, /etc/resolv.conf has nameserver entries) is there any reason why my pppd ms_dns options would list anything other than the contents of resolv.conf?...

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Thread: pppd and ms_dns

  1. pppd and ms_dns

    If I have Linux system with DNS configured (that is, /etc/resolv.conf
    has
    nameserver entries) is there any reason why my pppd ms_dns options
    would list anything other than the contents of resolv.conf?


  2. Re: pppd and ms_dns

    "Chris Nelson" writes:
    > If I have Linux system with DNS configured (that is, /etc/resolv.conf
    > has
    > nameserver entries) is there any reason why my pppd ms_dns options
    > would list anything other than the contents of resolv.conf?


    Sure. The 'ms-dns' pppd option gives DNS server addresses to the peer
    system using non-standard Microsoft extensions.

    For any of the same reasons that two systems might not have the same
    DNS server addresses configured, these might not be the same addresses
    as used on the local system.

    So, for, example, your local system might be a DNS server and thus
    have 127.0.0.1 configured in /etc/resolv.conf, but send out some
    routable address to the clients. Or your local system might be on a
    DMZ and resolve against an "external" server, while clients resolve
    against an "internal" one.

    There are any of a number of reasons why these might differ. It
    depends on your network topology and deployment.

    --
    James Carlson, KISS Network
    Sun Microsystems / 1 Network Drive 71.232W Vox +1 781 442 2084
    MS UBUR02-212 / Burlington MA 01803-2757 42.496N Fax +1 781 442 1677

  3. Re: pppd and ms_dns

    "Chris Nelson" writes:

    >If I have Linux system with DNS configured (that is, /etc/resolv.conf
    >has
    >nameserver entries) is there any reason why my pppd ms_dns options
    >would list anything other than the contents of resolv.conf?


    ms_dns is a way of asking the other side for dns servers. They are stored
    in /etc/ppp/resolv.conf. It is up to you (or the software) to transfer them
    to /etc/resolv.conf. (I assume you are asking where Linux is the one
    requesting ms_dns. )


  4. Re: pppd and ms_dns

    Unruh writes:

    > "Chris Nelson" writes:
    >
    > >If I have Linux system with DNS configured (that is, /etc/resolv.conf
    > >has
    > >nameserver entries) is there any reason why my pppd ms_dns options
    > >would list anything other than the contents of resolv.conf?

    >
    > ms_dns is a way of asking the other side for dns servers. They are stored
    > in /etc/ppp/resolv.conf. It is up to you (or the software) to transfer them
    > to /etc/resolv.conf. (I assume you are asking where Linux is the one
    > requesting ms_dns. )


    No. "ms-dns" provides addresses to the peer.

    The "usepeerdns" option does what you describe.

    --
    James Carlson, KISS Network
    Sun Microsystems / 1 Network Drive 71.232W Vox +1 781 442 2084
    MS UBUR02-212 / Burlington MA 01803-2757 42.496N Fax +1 781 442 1677

  5. Re: pppd and ms_dns

    Unruh wrote:
    > "Chris Nelson" writes:
    >
    > >If I have Linux system with DNS configured (that is, /etc/resolv.conf
    > >has nameserver entries) is there any reason why my pppd ms_dns
    > >options would list anything other than the contents of resolv.conf?

    >
    > ms_dns is a way of asking the other side for dns servers. They are stored
    > in /etc/ppp/resolv.conf. It is up to you (or the software) to transfer them
    > to /etc/resolv.conf. (I assume you are asking where Linux is the one
    > requesting ms_dns. )


    No, I'm configuring a Linux server and trying to decide what to put on
    the ms_dns lines of my pppd options file. I originally thought it
    would be what was in that server's resolv.conf but I see now that if
    the server is a DNS server, it would be the server's IP on the PPP link
    (so that the PPP client would ask the server for DNS stuff) or if the
    server is not a DNS server, it might be this server's resolv.conf
    values (where the client would likely use this server as a default
    gateway and DNS messages from the client would be forwarded).


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