Technically, that is not entirely true. If you look at the RFC
that governs NCP negotiation for IP(RFC 1332), it says this:
3.3. IP-Address
Description
This Configuration Option provides a way to negotiate the IP
address to be used on the local end of the link. It allows the
sender of the Configure-Request to state which IP-address is
desired, or to request that the peer provide the information.
The peer can provide this information by NAKing the option, and
returning a valid IP-address.
If negotiation about the remote IP-address is required, and the
peer did not provide the option in its Configure-Request, the
option SHOULD be appended to a Configure-Nak. The value of the
IP-address given must be acceptable as the remote IP-address,
or indicate a request that the peer provide the information.
By default, no IP address is assigned.
In order to get an ACK, you will need a response from the
access server to provide an IP address. Normally, when a
request is made with an IP address of 0.0.0.0, that will
normally trigger an RFC 1541 DHCP discover. The access server
can be configured to either pass along this request for DHCP
assigned information, including any standard DHCP options (IP
addr, mask, DNS, WINs, etc.), or it can use a statically
assigned values you have configured on the access server.
There are merits to doing it both ways.
As far as windows, assigning a /32 mask to all IP assignments
via a dialup connection, I must confess I have not seen this
phenomenon. I decided to dial Netzero's network twice for a
test. Here is what I received:
F:\>ipconfig /all
Windows NT IP Configuration
Host Name . . . . . . . . . : wernerpd
DNS Servers . . . . . . . . : 209.247.163.218
209.247.163.216
PPP adapter NdisWan5:
Description . . . . . . . . : NdisWan Adapter
Physical Address. . . . . . : 00-01-d0-2e-9c-80
DHCP Enabled. . . . . . . . : No
IP Address. . . . . . . . . : 209.244.227.9
Subnet Mask . . . . . . . . : 255.255.255.0
Default Gateway . . . . . . : 209.244.227.9
LAN NIC assigned DNS values are as follows:
207.217.77.82
207.217.120.83
207.217.126.81
I then dialed the network again:
F:\>ipconfig /all
Windows NT IP Configuration
Host Name . . . . . . . . . : wernerpd
DNS Servers . . . . . . . . : 209.247.163.218
209.247.163.216
PPP adapter NdisWan5:
Description . . . . . . . . : NdisWan Adapter
Physical Address. . . . . . : 00-01-d0-2e-9c-80
DHCP Enabled. . . . . . . . : No
IP Address. . . . . . . . . : 63.215.152.226
Subnet Mask . . . . . . . . : 255.0.0.0
Default Gateway . . . . . . : 63.215.152.226
Note that in both instances, DHCP was not used for IP
assignment, so this would seem to indicate that these values
were manually assigned on the access servers.
v/r,
Paul Werner
> He is right. You can pass DNS and WINS information,
> but subnet mask and stuff won't be in there. I don't
> believe there is even a field in the IPCP packet for
> that. Don't worry about what ipconfig says. It works
> right? :)
>
>
>
> - --- nrf wrote:
> > Strange, I was able to pass information like DNS and
> > WINS to the client just
> > fine on my access-server, using async-bootp.
> >
> > Note, you generally don't need to pass things like
> > subnet mask or GW to the
> > client anyway. If you are using normal IPCP
> > negotiations, then the address
> > of the access-server gets passed to the client as a
> > host route. And
> > whatever address the access-server hands to the
> > client, Windows
> > automatically gives it a /32 mask, even if you try
> > to negotiate some other
> > mask (I'm sure this behavior can be changed
> > somewhere in the registry, I
> > just don't know how, and besides, I don't know why
> > you would want to). And
> > by default in Windows, once a dial PPP session has
> > been negotiated, Windows
> > uses that PPP session as a default gateway
> > automatically, so your
> > access-server doesn't need to hand default gateway
> > information to the
> > client. You can turn this behavior off, if you
> > want.
> > >
> > > NetEng wrote:
> > >
> > > > I have a 2600 w/ NM16AM, I have it configured
> > and it works like a champ
> > > > except for one thing. How do I pass network
> > parameters to the client? I
> > > need
> > > > to specify the subnet mask, default gw, dns,
> > etc. I tried the
> > async-bootp
> > > > command from global config, but that didnt work.
> > I created the ip pool
> > just
> > > > fine, but I cant find where to set the rest of
> > the info. TIA.
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