DHCP client assigns an invalid hostname (RH9)
Rick Stevens
rstevens at vitalstream.com
Tue Aug 3 17:26:26 UTC 2004
Aubrey Barnard wrote:
> To whomever may be kind enough to answer:
>
> My problem is that I have been assigned an invalid hostname on my RH9
> system.
>
> I started getting cable internet service from Charter earlier this summer.
> My previous ISP and network administration was my college. Since starting
> with Charter, I have not been assigned a proper host name. I contacted
> Charter, but they didn't think there was anything wrong, so I am trying
> here to see if it is possibly a client-side issue. No issue existed when
> on my college network.
>
> When I boot my computer, I am assigned a hostname such as 'dhcp-521-7' (it
> varies). The problem is that I cannot (and certain programs cannot)
> resolve this to an IP address. Essentially, the hostname I am assigned
> does not match what the DNS servers say that my hostname should be. For
> example, 'hostname -i' fails, and so does the library call
> 'gethostbyname'. To illustrate, I give the following outputs. Running
> ifconfig produces the following:
>
> # ifconfig
> eth0 Link encap:Ethernet HWaddr 00:02:B3:B6:A8:C1
> inet addr:68.190.160.235 Bcast:255.255.255.255
> Mask:255.255.240.0
> UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
> RX packets:1507398 errors:0 dropped:0 overruns:0 frame:0
> TX packets:75664 errors:0 dropped:0 overruns:0 carrier:0
> collisions:0 txqueuelen:100
> RX bytes:115176823 (109.8 Mb) TX bytes:6818394 (6.5 Mb)
> Interrupt:5 Base address:0xd000 Memory:d5000000-d5000038
>
> lo Link encap:Local Loopback
> inet addr:127.0.0.1 Mask:255.0.0.0
> UP LOOPBACK RUNNING MTU:16436 Metric:1
> RX packets:203 errors:0 dropped:0 overruns:0 frame:0
> TX packets:203 errors:0 dropped:0 overruns:0 carrier:0
> collisions:0 txqueuelen:0
> RX bytes:134774 (131.6 Kb) TX bytes:134774 (131.6 Kb)
>
> These are my leases:
>
> # more /var/lib/dhcp/dhclient-eth0.leases
> lease {
> interface "eth0";
> fixed-address 68.190.160.235;
> option subnet-mask 255.255.240.0;
> option time-offset -21600;
> option dhcp-lease-time 25982;
> option routers 68.190.160.1;
> option dhcp-message-type 5;
> option dhcp-server-identifier 68.115.71.9;
> option domain-name-servers 68.115.71.53,24.159.193.40,24.159.222.40;
> option broadcast-address 255.255.255.255;
> option host-name "dhcp-521-7";
> option domain-name "eau.wi.charter.com";
> renew 1 2004/7/26 07:50:21;
> rebind 1 2004/7/26 11:01:34;
> expire 1 2004/7/26 11:55:42;
> }
> lease {
> interface "eth0";
> fixed-address 68.190.160.235;
> option subnet-mask 255.255.240.0;
> option time-offset -21600;
> option routers 68.190.160.1;
> option dhcp-lease-time 25640;
> option dhcp-message-type 5;
> option domain-name-servers 68.115.71.53,24.159.193.40,24.159.222.40;
> option dhcp-server-identifier 68.115.71.9;
> option broadcast-address 255.255.255.255;
> option host-name "dhcp-521-7";
> option domain-name "eau.wi.charter.com";
> renew 1 2004/7/26 08:05:02;
> rebind 1 2004/7/26 11:02:17;
> expire 1 2004/7/26 11:55:42;
> }
>
> The conflict begins when host (or dig) reports a hostname different from
> above:
>
> # host -v 68.190.160.235
> Trying "235.160.190.68.in-addr.arpa"
> ;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 29783
> ;; flags: qr rd ra; QUERY: 1, ANSWER: 1, AUTHORITY: 2, ADDITIONAL: 1
>
> ;; QUESTION SECTION:
> ;235.160.190.68.in-addr.arpa. IN PTR
>
> ;; ANSWER SECTION:
> 235.160.190.68.in-addr.arpa. 32733 IN PTR
> c68.190.160.235.eau.wi.charter.com.
>
> ;; AUTHORITY SECTION:
> 160.190.68.in-addr.arpa. 32733 IN NS ns1.jvl.wi.charter.com.
> 160.190.68.in-addr.arpa. 32733 IN NS ns1.mazo.wi.charter.com.
>
> ;; ADDITIONAL SECTION:
> ns1.mazo.wi.charter.com. 32937 IN A 24.158.0.10
>
> Received 154 bytes from 130.71.128.8#53 in 62 ms
>
> I see from this that my hostname should be
> 'c68.190.160.235.eau.wi.charter.com', which is what the technical support
> at Charter told me. My question is whether there is something I can do to
> make the hostnames agree. Any help would be greatly appreciated. I have
> included (hopefully) relevant files below.
>
> Sincerely,
> Aubrey Barnard
>
> P.S. This problem has not caused any visible lack of functionality except
> that Gnome reports an error and my network usage is quite high until I
> first open a web browser.
>
> # more /etc/resolv.conf
> ; generated by /sbin/dhclient-script
> nameserver 130.71.128.8
> nameserver 130.71.96.8
> search acc.stolaf.edu
>
> The file '/etc/dhclient.conf' does not exist.
I don't have an RH9 system handy, but the file could be named any number
of things. It could be named "dhclient.conf" or "dhclient-eth0.conf" or
some other permutation and it may not be in /etc, but rather in
/etc/dhclient, as in "/etc/dhclient/dhclient-eth0.conf". So, first:
cd /etc
Then:
ls -ld dh*
If you get back a "dhclient" directory, then "cd /etc/dhclient" and look
in there for the file. Once you find the file, it should contain
something like:
interface "eth0" {
request subnet-mask, broadcast_address, routers;
request domain-name-servers, host-name;
require subnet-mask, routers;
}
That means that your machine will request an IP address, subnet mask,
broadcast address, router, DNS servers AND the host name, and that for
DHCP to work, the DHCP server MUST give you the IP, subnet mask and
router.
Note that your X stuff may not work, since it was set up with one host
name and you'll be getting a new one. Ideally, you should remove the
"host-name" request above and simply set the host name to "localhost"
in /etc/sysconfig/network.
----------------------------------------------------------------------
- Rick Stevens, Senior Systems Engineer rstevens at vitalstream.com -
- VitalStream, Inc. http://www.vitalstream.com -
- -
- Blech! ACKth! Ooop! -- Bill the Cat (Outland) -
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