DHCP misunderstanding.

QNX Newsgroups (Archives) qdn.public.qnxrtp.installation
1

Currently I have the RTP set up to use DHCP to get an IP address from some
server that our IT department controls. Given the the propensity of our
corporate environment to use the “tried and true” sighs Microsoft products
it is probably an NT box.

It gives me an IP address all right… however I can’t seem to get it to
link up my hostname to the IP address that they gave me. So any ‘nslookup’
doesn’t let me talk to the box.

What might I be doing wrong… Or is this a bug on the server side?

Carey Duran

2

Interoperations between DHCP and DNS aren’t well standartized (or they
aren’t well implemented anyway). I think M$ does something proprietary
to sync DNS with DHCP (actually i suspect they use WINS with DHCP).

Carey Duran wrote:

Currently I have the RTP set up to use DHCP to get an IP address from some
server that our IT department controls. Given the the propensity of our
corporate environment to use the “tried and true” sighs Microsoft products
it is probably an NT box.

It gives me an IP address all right… however I can’t seem to get it to
link up my hostname to the IP address that they gave me. So any ‘nslookup’
doesn’t let me talk to the box.

What might I be doing wrong… Or is this a bug on the server side?

Carey Duran

3

Carey Duran <cduran@harscotrack.com> wrote:

Currently I have the RTP set up to use DHCP to get an IP address from some
server that our IT department controls. Given the the propensity of our
corporate environment to use the “tried and true” sighs Microsoft products
it is probably an NT box.

It gives me an IP address all right… however I can’t seem to get it to
link up my hostname to the IP address that they gave me. So any ‘nslookup’
doesn’t let me talk to the box.

What might I be doing wrong… Or is this a bug on the server side?

After you boot RTP, do a “getconf CS_RESOLVE” see if you get a resolver.
If so, you probably OK to ping/telnet other boxes with name.

If you don’t have one, more likely your NT didn’t setup to give you
a DNS. You might be staticly add it by running phlip.

nslookup is another issue. It ONLY using /etc/resolv.conf to find
it’s own resolver. As we by default, don’t create that file, nslookup
won’t success anyway. (you need to create that file yourself if you
want to use nslookup).

-xtang

4

“Xiaodan Tang” <xtang@qnx.com> wrote in message
news:8qvq15$a5c$1@nntp.qnx.com…

Carey Duran <> cduran@harscotrack.com> > wrote:
Currently I have the RTP set up to use DHCP to get an IP address from
some
server that our IT department controls. Given the the propensity of our
corporate environment to use the “tried and true” sighs Microsoft
products
it is probably an NT box.

It gives me an IP address all right… however I can’t seem to get it to
link up my hostname to the IP address that they gave me. So any
‘nslookup’
doesn’t let me talk to the box.

What might I be doing wrong… Or is this a bug on the server side?

After you boot RTP, do a “getconf CS_RESOLVE” see if you get a resolver.
If so, you probably OK to ping/telnet other boxes with name.

If you don’t have one, more likely your NT didn’t setup to give you
a DNS. You might be staticly add it by running phlip.

nslookup is another issue. It ONLY using /etc/resolv.conf to find
it’s own resolver. As we by default, don’t create that file, nslookup
won’t success anyway. (you need to create that file yourself if you
want to use nslookup).

‘getconf CS_RESOLVE’ yields:
lookup_file_bind
nameserver_10.30.16.1

Which appears correct.

My ‘/etc/resolv.conf’ file looks like:

domain fmttmpr.harsco.com
nameserver 10.30.16.1

Which appears correct as well.

My Windows partition can register it’s name. And I can ping it by name from
QNX (RTP and 4.25) but the 4.25 and RTP guys can’t/aren’t register their
names.

This is looking more like a server problem to me as I get deeper into it. If
there aren’t any more suggestions, is there a way of getting around this by
running my own name server and passing on the unknown request to the “real”
server.

Carey Duran

5

Carey Duran <cduran@harscotrack.com> wrote:

“Xiaodan Tang” <> xtang@qnx.com> > wrote in message
news:8qvq15$a5c$> 1@nntp.qnx.com> …
Carey Duran <> cduran@harscotrack.com> > wrote:
Currently I have the RTP set up to use DHCP to get an IP address from
some
server that our IT department controls. Given the the propensity of our
corporate environment to use the “tried and true” sighs Microsoft
products
it is probably an NT box.

It gives me an IP address all right… however I can’t seem to get it to
link up my hostname to the IP address that they gave me. So any
‘nslookup’
doesn’t let me talk to the box.

What might I be doing wrong… Or is this a bug on the server side?

After you boot RTP, do a “getconf CS_RESOLVE” see if you get a resolver.
If so, you probably OK to ping/telnet other boxes with name.

If you don’t have one, more likely your NT didn’t setup to give you
a DNS. You might be staticly add it by running phlip.

nslookup is another issue. It ONLY using /etc/resolv.conf to find
it’s own resolver. As we by default, don’t create that file, nslookup
won’t success anyway. (you need to create that file yourself if you
want to use nslookup).

‘getconf CS_RESOLVE’ yields:
lookup_file_bind
nameserver_10.30.16.1

Which appears correct.

My ‘/etc/resolv.conf’ file looks like:

domain fmttmpr.harsco.com
nameserver 10.30.16.1

Which appears correct as well.

So for start, can you “ping 10.30.16.1” from RTP box?

If you do “nslookup”, is it saying “server 10.30.16.1” ?

My Windows partition can register it’s name. And I can ping it by name from
QNX (RTP and 4.25) but the 4.25 and RTP guys can’t/aren’t register their
names.

I don’t now what you mean “register name”.

Are you saying on the RTP box, you could “ping name_of_my_windows”, but
from windows, you can’t “ping name_of_my_rtp” ?

Since your RTP is a dhcp client, are you sure you know the right name?
And if you can’t ping RTP from windows, that’s problem in windows/DNS
server. Can you “ping ip_of_my_rtp” from windows?

This is looking more like a server problem to me as I get deeper into it. If
there aren’t any more suggestions, is there a way of getting around this by
running my own name server and passing on the unknown request to the “real”
server.

I don’t think named is shipped. You can start named on 4.25 box though,
make it a “cache only” server.

-xtang

6

“Xiaodan Tang” <xtang@ottawa.com> wrote in message
news:8r004s$dpr$1@nntp.qnx.com…

Carey Duran <> cduran@harscotrack.com> > wrote:
“Xiaodan Tang” <> xtang@qnx.com> > wrote in message
news:8qvq15$a5c$> 1@nntp.qnx.com> …
Carey Duran <> cduran@harscotrack.com> > wrote:
Currently I have the RTP set up to use DHCP to get an IP address from
some
server that our IT department controls. Given the the propensity of
our
corporate environment to use the “tried and true” sighs Microsoft
products
it is probably an NT box.

It gives me an IP address all right… however I can’t seem to get it
to
link up my hostname to the IP address that they gave me. So any
‘nslookup’
doesn’t let me talk to the box.

What might I be doing wrong… Or is this a bug on the server side?

After you boot RTP, do a “getconf CS_RESOLVE” see if you get a
resolver.
If so, you probably OK to ping/telnet other boxes with name.

If you don’t have one, more likely your NT didn’t setup to give you
a DNS. You might be staticly add it by running phlip.

nslookup is another issue. It ONLY using /etc/resolv.conf to find
it’s own resolver. As we by default, don’t create that file, nslookup
won’t success anyway. (you need to create that file yourself if you
want to use nslookup).

‘getconf CS_RESOLVE’ yields:
lookup_file_bind
nameserver_10.30.16.1

Which appears correct.

My ‘/etc/resolv.conf’ file looks like:

domain fmttmpr.harsco.com
nameserver 10.30.16.1

Which appears correct as well.

So for start, can you “ping 10.30.16.1” from RTP box?

Yes

If you do “nslookup”, is it saying “server 10.30.16.1” ?

Yes

My Windows partition can register it’s name. And I can ping it by name
from
QNX (RTP and 4.25) but the 4.25 and RTP guys can’t/aren’t register their
names.

I don’t now what you mean “register name”.

Are you saying on the RTP box, you could “ping name_of_my_windows”, but
from windows, you can’t “ping name_of_my_rtp” ?

This is correct. I’ve set hostname ‘duran’ in my windows box, and I can
‘ping duran’ from the RTP. I then set hostname ‘duran2’ (using ‘Network
Cfg’) in my RTP box, but I cannot ‘ping duran2’ from the windows box.

Since your RTP is a dhcp client, are you sure you know the right name?
And if you can’t ping RTP from windows, that’s problem in windows/DNS
server. Can you “ping ip_of_my_rtp” from windows?

Hmmmm… the “Right Name”? I can change my hostname in Windows and reboot
and it gets the new host. Am I going to have to pester IT to get this set
up properly? I thought this was being sent as a parameter to dhcp.client.

This is looking more like a server problem to me as I get deeper into
it. If
there aren’t any more suggestions, is there a way of getting around this
by
running my own name server and passing on the unknown request to the
“real”
server.

I don’t think named is shipped. You can start named on 4.25 box though,
make it a “cache only” server.

-xtang

I’ll have to look into this.

Carey

7

DHCP & DNS are totally unrelated, so DNS has no way of knowing what machine
name is currently using an IP out of the DHCP address pool. That is why when
you do a reverse lookup on the IP you get it is always a generic name.

PC’s talking to PC’s that also have WINS set up don’t see the issue because
when DNS fails they fall back to WINS which usually works, but won’t if the
machine being looked up isn’t a PC or isn’t registered in WINS currently.

The most recent versions of the DNS daemon allow for dynamic IP’s and for
machines to send the dhcp server their name, but this depends on your client
machine knowing to register it’s name & IP with the DNS server as well as
your company/ISP to be running the DNS daemon that supports this…

Windows 2000 has the best solution I’m aware of - the DHCP server will
update the DNS server on behalf of clients that don’t know how to update the
DNS server on their own (this also gets around the security issue involved
in letting clients update the DNS server’s tables). This is even less likely
to help you though, since obviously that isn’t what is happening for you…

Short answer, if you aren’t running WINS, and the people trying to look you
up aren’t running WINS, and your DNS server doesn’t support client updates
of the tables, there isn’t anything you can do… Other than a 3rd-party IP
registration service like you might use to let people find you via your
ISP…

8

Marisa Giancarla wrote:

Short answer, if you aren’t running WINS, and the people trying to look you
up aren’t running WINS, and your DNS server doesn’t support client updates
of the tables, there isn’t anything you can do… Other than a 3rd-party IP
registration service like you might use to let people find you via your
ISP…

You could have the DCHPD configured to give you a static IP address
and have your DNS configured with a static name.

9

“Norton Allen” <allen@huarp.harvard.edu> wrote in message
news:39F04279.E662800F@huarp.harvard.edu…

You could have the DCHPD configured to give you a static IP address
and have your DNS configured with a static name.

Yes of course, but that assumes you are an admin of both the dhcp server and
dns server, which isn’t going to be true for most people forced to use DHCP,
and that will only work if you use the same ethernet card, otherwise the MAC
address will be different and you won’t get your same IP…

Marisa…