DHCPCD fails on Linux PC

DHCPCD fails to obtain on ip # on my linux box from my ISP - Cox
Communications.

This is my setup:

cox network <----------> cable modem <--------> PC NIC

Both tech support at Cox Communications and my own tests prove that
my ability to obtain an ip from their DHCP servers should depend only on
the cable modem MAC address.

If "PC NIC" is my SuSE 8.0 Box obtaining an ip address thru DHCPCD, I get
with command: dhcpcd -d eth0

dhcpcd.log as follows:

Dec 11 15:29:53 opal dhcpcd[1011]: broadcasting DHCP_DISCOVER
Dec 11 15:29:53 opal dhcpcd[1011]: broadcastAddr option is missing in DHCP
server response. Assuming 68.100.187.255
Dec 11 15:29:53 opal dhcpcd[1011]: dhcpT1value option is missing in DHCP
server response. Assuming 43200 sec
Dec 11 15:29:53 opal dhcpcd[1011]: dhcpT2value option is missing in DHCP
server response. Assuming 75600 sec
Dec 11 15:29:53 opal dhcpcd[1011]: DHCP_OFFER received from (172.19.105.19)
Dec 11 15:29:53 opal dhcpcd[1011]: broadcasting DHCP_REQUEST for
68.100.184.95
Dec 11 15:29:53 opal dhcpcd[1011]: DHCP_NAK server response received:
requested address not available

Repeated about 20-50 times, until the DHCP server refuses to respond.

Dec 11 15:55:23 opal dhcpcd[1127]: DHCP_NAK server response received:
requested address not available
Dec 11 15:55:23 opal dhcpcd[1127]: broadcasting DHCP_DISCOVER
Dec 11 15:55:23 opal dhcpcd[1127]: timed out waiting for a valid DHCP server
response
Dec 11 15:55:23 opal dhcpcd[1127]: modify_resolvconf restore
Dec 11 15:55:23 opal dhcpcd[1127]: modify_resolvconf returns 0


OK, So Now I replace the PC in "PC NIC" with a Windows 98 computer.
Then it all works fine!! I get an ip, I'm online.

So what's happening with DHCPCD? I've tried cycling the cable modem, to no
avail. I can't figure why the server refuses the DHCP_REQUEST, and I don't
know how to further diagnose the problem further with tcpdump because it
won't work until the interface is configured! (chicken and egg problem)
tcpdump can only give the following error message:

cpdump: WARNING: eth1: no IPv4 address assigned
tcpdump: listening on eth1
tcpdump: pcap_loop: recvfrom: Network is down


Please can anybody help !!
Really stuck!

George

--
#
#...

George Bell wrote:

> DHCPCD fails to obtain on ip # on my linux box from my ISP - Cox
> Communications.
>
> This is my setup:
>
> cox network <----------> cable modem <--------> PC NIC
>
> Both tech support at Cox Communications and my own tests prove that
> my ability to obtain an ip from their DHCP servers should depend only on
> the cable modem MAC address.

It should be the cable modem MAC address to log onto their network and your
original computers MAC to get a IP from them. I had to use my MAC address
from the computer that I originally setup my account with to log on.

[snip]

Synchrodude wrote:

> George Bell wrote:
>
>> DHCPCD fails to obtain on ip # on my linux box from my ISP - Cox
>> Communications.
>>
>> This is my setup:
>>
>> cox network <----------> cable modem <--------> PC NIC
>>
>> Both tech support at Cox Communications and my own tests prove that
>> my ability to obtain an ip from their DHCP servers should depend only on
>> the cable modem MAC address.
>
> It should be the cable modem MAC address to log onto their network and
> your original computers MAC to get a IP from them. I had to use my MAC
> address from the computer that I originally setup my account with to log
> on.
>
> [snip]
Then how do you explain my results: I'm able to get an ip whenever "PC NIC"
is either a Linksys Router or a Windows 98 computer, but not my linux PC.
Furthermore, Cox tech support tells me that only the MAC address of the
cable modem should matter.

I have a little more information on this now. I've modified my network
slightly to facilitate testing:




cox network <------->cable modem <-------->hub <-------PC NIC DHCPCD (eth1)
<-------PC NIC w/ reserved ip
(eth0)
The second NIC is to "spy" on the other with tcpdump. Of course, this is
not correct because it puts a reserved ip on the same network as the other.
But since its only reading packets off the network, and not sending any, it
appears to work. This is the output of tcpdump listening in on eth0:


09:15:57.548959 0.0.0.0.bootpc > 255.255.255.255.bootps: xid:0xc8537b01
secs:10 vend-rfc1048 DHCP:REQUEST MSZ:548 SID:172.19.105.19
RQ:68.100.184.95 LT:86400
PR:SM+DG+NS+HN+DN+RP+TTL+BR+MD+RD+SR+YD+YS+NTP+LPR +LOG+T-56
VC:76.105.110.117.120.32.50.46.52.46.49.56.45.52.7 1.66.32.105.53.56.54
CID:01:00:30:84:6d:a8:a7
09:15:57.569937 10.2.0.1.bootps > 255.255.255.255.bootpc: xid:0xc8537b01
secs:10 flags:0x8000 S:172.19.105.19 G:10.2.0.1 ether 0:30:84:6d:a8:a7
vend-rfc1048 DHCP:NACK MSG:"requested address not available" [tos
0x7,ECT,CE]
09:15:57.570581 0.0.0.0.bootpc > 255.255.255.255.bootps: xid:0x86272f60
secs:10 vend-rfc1048 DHCPISCOVER MSZ:548 RQ:68.100.184.95 LT:4294967295
PR:SM+DG+NS+HN+DN+RP+TTL+BR+MD+RD+SR+YD+YS+NTP+LPR +LOG+T-56
VC:76.105.110.117.120.32.50.46.52.46.49.56.45.52.7 1.66.32.105.53.56.54
CID:01:00:30:84:6d:a8:a7
09:15:57.576548 arp who-has 68.100.126.150 tell 68.100.112.1
09:15:57.604571 arp who-has 68.100.118.201 tell 68.100.112.1
09:15:57.606106 0.0.0.0.bootpc > 255.255.255.255.bootps: xid:0x86272f60
secs:10 vend-rfc1048 DHCP:REQUEST MSZ:548 SID:172.19.105.19
RQ:68.100.184.95 LT:86400
PR:SM+DG+NS+HN+DN+RP+TTL+BR+MD+RD+SR+YD+YS+NTP+LPR +LOG+T-56
VC:76.105.110.117.120.32.50.46.52.46.49.56.45.52.7 1.66.32.105.53.56.54
CID:01:00:30:84:6d:a8:a7
09:15:57.611617 arp who-has 68.100.118.85 tell 68.100.112.1
09:15:57.623854 arp who-has 68.100.184.58 tell 68.100.184.1
09:15:57.629636 10.2.0.1.bootps > 255.255.255.255.bootpc: xid:0x86272f60
secs:10 flags:0x8000 S:172.19.105.19 G:10.2.0.1 ether 0:30:84:6d:a8:a7
vend-rfc1048 DHCP:NACK MSG:"requested address not available" [tos
0x7,ECT,CE]
09:15:57.630182 0.0.0.0.bootpc > 255.255.255.255.bootps: xid:0xaeaa3e5b
secs:10 vend-rfc1048 DHCPISCOVER MSZ:548 RQ:68.100.184.95 LT:4294967295
PR:SM+DG+NS+HN+DN+RP+TTL+BR+MD+RD+SR+YD+YS+NTP+LPR +LOG+T-56
VC:76.105.110.117.120.32.50.46.52.46.49.56.45.52.7 1.66.32.105.53.56.54
CID:01:00:30:84:6d:a8:a7
09:15:57.634130 arp who-has 68.100.123.26 tell 68.100.112.1
09:15:57.639157 arp who-has 68.100.184.65 tell 68.100.184.1
09:15:57.654332 0.0.0.0.bootpc > 255.255.255.255.bootps: xid:0xaeaa3e5b
secs:10 vend-rfc1048 DHCP:REQUEST MSZ:548 SID:172.19.105.19
RQ:68.100.184.95 LT:86400
PR:SM+DG+NS+HN+DN+RP+TTL+BR+MD+RD+SR+YD+YS+NTP+LPR +LOG+T-56
VC:76.105.110.117.120.32.50.46.52.46.49.56.45.52.7 1.66.32.105.53.56.54
CID:01:00:30:84:6d:a8:a7
09:15:57.674967 arp who-has 68.100.127.38 tell 68.100.112.1
09:15:57.678387 10.2.0.1.bootps > 255.255.255.255.bootpc: xid:0xaeaa3e5b
secs:10 flags:0x8000 S:172.19.105.19 G:10.2.0.1 ether 0:30:84:6d:a8:a7
vend-rfc1048 DHCP:NACK MSG:"requested address not available" [tos
0x7,ECT,CE]
09:15:57.678926 0.0.0.0.bootpc > 255.255.255.255.bootps: xid:0x33b2cb4c
secs:10 vend-rfc1048 DHCPISCOVER MSZ:548 RQ:68.100.184.95 LT:4294967295
PR:SM+DG+NS+HN+DN+RP+TTL+BR+MD+RD+SR+YD+YS+NTP+LPR +LOG+T-56
VC:76.105.110.117.120.32.50.46.52.46.49.56.45.52.7 1.66.32.105.53.56.54
CID:01:00:30:84:6d:a8:a7
09:15:57.687276 arp who-has 68.100.126.157 tell 68.100.112.1
09:15:57.703279 0.0.0.0.bootpc > 255.255.255.255.bootps: xid:0x33b2cb4c
secs:10 vend-rfc1048 DHCP:REQUEST MSZ:548 SID:172.19.105.19
RQ:68.100.184.95 LT:86400
PR:SM+DG+NS+HN+DN+RP+TTL+BR+MD+RD+SR+YD+YS+NTP+LPR +LOG+T-56
VC:76.105.110.117.120.32.50.46.52.46.49.56.45.52.7 1.66.32.105.53.56.54
CID:01:00:30:84:6d:a8:a7
09:15:57.722602 10.2.0.1.bootps > 255.255.255.255.bootpc: xid:0x33b2cb4c
secs:10 flags:0x8000 S:172.19.105.19 G:10.2.0.1 ether 0:30:84:6d:a8:a7
vend-rfc1048 DHCP:NACK MSG:"requested address not available" [tos
0x7,ECT,CE]
09:15:57.723143 0.0.0.0.bootpc > 255.255.255.255.bootps: xid:0x5d20a823
secs:10 vend-rfc1048 DHCPISCOVER MSZ:548 RQ:68.100.184.95 LT:4294967295
PR:SM+DG+NS+HN+DN+RP+TTL+BR+MD+RD+SR+YD+YS+NTP+LPR +LOG+T-56
VC:76.105.110.117.120.32.50.46.52.46.49.56.45.52.7 1.66.32.105.53.56.54
CID:01:00:30:84:6d:a8:a7
09:15:57.750987 arp who-has 68.100.5.139 tell 68.100.4.1
09:15:57.757096 0.0.0.0.bootpc > 255.255.255.255.bootps: xid:0x5d20a823
secs:10 vend-rfc1048 DHCP:REQUEST MSZ:548 SID:172.19.105.19
RQ:68.100.184.95 LT:86400
PR:SM+DG+NS+HN+DN+RP+TTL+BR+MD+RD+SR+YD+YS+NTP+LPR +LOG+T-56
VC:76.105.110.117.120.32.50.46.52.46.49.56.45.52.7 1.66.32.105.53.56.54
CID:01:00:30:84:6d:a8:a7
09:15:57.779852 10.2.0.1.bootps > 255.255.255.255.bootpc: xid:0x5d20a823
secs:10 flags:0x8000 S:172.19.105.19 G:10.2.0.1 ether 0:30:84:6d:a8:a7
vend-rfc1048 DHCP:NACK MSG:"requested address not available" [tos
0x7,ECT,CE]
09:15:57.780374 0.0.0.0.bootpc > 255.255.255.255.bootps: xid:0xe5ce0a11
secs:10 vend-rfc1048 DHCPISCOVER MSZ:548 RQ:68.100.184.95 LT:4294967295
PR:SM+DG+NS+HN+DN+RP+TTL+BR+MD+RD+SR+YD+YS+NTP+LPR +LOG+T-56
VC:76.105.110.117.120.32.50.46.52.46.49.56.45.52.7 1.66.32.105.53.56.54
CID:01:00:30:84:6d:a8:a7
09:15:57.798326 arp who-has 68.100.126.160 tell 68.100.112.1
09:15:57.812108 arp who-has 68.105.182.105 tell 68.105.176.1



Note that: DHCPCD is constantly asking for the address 168.100.184.95
and the server responds with a NAK

Why does it do this !? And there's never any DHCP OFFER messages.
Furthermore, the files dhcpdcd-eth1.cache, dhcpcd-eth1.info are nonexistant
anywhere on the disk. There was supposed to be, I think, a file dhcpcd.exe
or dhcpcd-eth1.exe installed somewhere, but my distro - SUSE 8.0 didn't. I
istalled these files in /sbin but it didn't make any difference.

Great thanks to the previous poster's reply, and any others that could shed
some light on this.

George

--
#
#...

Synchrodude wrote:

> George Bell wrote:
>
>> DHCPCD fails to obtain on ip # on my linux box from my ISP - Cox
>> Communications.
>>
>> This is my setup:
>>
>> cox network <----------> cable modem <--------> PC NIC
>>
>> Both tech support at Cox Communications and my own tests prove that
>> my ability to obtain an ip from their DHCP servers should depend only on
>> the cable modem MAC address.
>
> It should be the cable modem MAC address to log onto their network and
> your original computers MAC to get a IP from them. I had to use my MAC
> address from the computer that I originally setup my account with to log
> on.
>
> [snip]

OK IT WORKS !!!!! YAY !!!!!

It seems you are right. The way I fixed this, was to take out the NIC on
the windows computer that was working, and switched it with the one in the
Linux PC. Low and behold... my interface on the Linux PC was configured
with the same IP that was on the Windows computer.

(B.T.W. My "spy setup" was giving incomplete information. It turned out
that my hub(a Linksys 8 port) must have been doing some caching of hardware
addresses. When I used dhcpcd with the -B (tell server send replies in
Broadcast) I could then detect the server's DHCP OFFER packets. )

Cox allows two IPs. I'm using one on a router already with which I'm using
for the computer to send this e-mail on. I guess I "used up" the second
one when I was testing with the windows computer. I don't know why it
didn't work in the beginning before I began testing with the windows
computer(maybe because I didn't power cycle the cable modem?), but I'll
take it !!!!

Thanks for the feedback and the help !!

George

--
#
#...

In message <Q6qCb.4576$hf1.3333@lakeread06>, George Bell wrote:

>
> It seems you are right. The way I fixed this, was to take out the NIC on
> the windows computer that was working, and switched it with the one in the
> Linux PC. Low and behold... my interface on the Linux PC was configured
> with the same IP that was on the Windows computer.
>
Provided you are careful (i.e. don't have both on the net together) you can
(at least with RedHat) define MACADDR=AA:BB:CCD:EE:FF in the config file
(/etc/sysconfig/network-scripts/ifcfg-eth? on my router)

That's how I switched from a Linksys router to a Linux box without
disturbing the outside world, I just copied the mac address.

Dave
--
mail: da (E-Mail Removed) (without the space)
http://www.llondel.org/
So many gadgets, so little time...

Dave {Reply Address in.sig} wrote:

> In message <Q6qCb.4576$hf1.3333@lakeread06>, George Bell wrote:
>
>>
>> It seems you are right. The way I fixed this, was to take out the NIC
>> on the windows computer that was working, and switched it with the one in
>> the
>> Linux PC. Low and behold... my interface on the Linux PC was configured
>> with the same IP that was on the Windows computer.
>>
> Provided you are careful (i.e. don't have both on the net together) you
> can (at least with RedHat) define MACADDR=AA:BB:CCD:EE:FF in the config
> file (/etc/sysconfig/network-scripts/ifcfg-eth? on my router)
>
> That's how I switched from a Linksys router to a Linux box without
> disturbing the outside world, I just copied the mac address.
>
> Dave


THANKS FOR THE TIP!

I indeed do hope to get rid of the Linksys router at some point.
Thats a lot better than my other plan:

1) Take out the router and directly connect to a windows computer, because
that's all Cox tech support will help you with.
2) Complain when it doesn't work( which it will).
3) After Cox has got that working, install the NIC in the pc you really want
to use on.

George

--
#
#...

George Bell wrote:

> Synchrodude wrote:
>
>> George Bell wrote:
>>
>>> DHCPCD fails to obtain on ip # on my linux box from my ISP - Cox
>>> Communications.
>>>
>>> This is my setup:
>>>
>>> cox network <----------> cable modem <--------> PC NIC
>>>
>>> Both tech support at Cox Communications and my own tests prove that
>>> my ability to obtain an ip from their DHCP servers should depend only on
>>> the cable modem MAC address.
>>
>> It should be the cable modem MAC address to log onto their network and
>> your original computers MAC to get a IP from them. I had to use my MAC
>> address from the computer that I originally setup my account with to log
>> on.
>>
>> [snip]
>
> OK IT WORKS !!!!! YAY !!!!!
>
> It seems you are right. The way I fixed this, was to take out the NIC on
> the windows computer that was working, and switched it with the one in the
> Linux PC. Low and behold... my interface on the Linux PC was configured
> with the same IP that was on the Windows computer.
>
> (B.T.W. My "spy setup" was giving incomplete information. It turned out
> that my hub(a Linksys 8 port) must have been doing some caching of
> hardware
> addresses. When I used dhcpcd with the -B (tell server send replies in
> Broadcast) I could then detect the server's DHCP OFFER packets. )
>
> Cox allows two IPs. I'm using one on a router already with which I'm
> using
> for the computer to send this e-mail on. I guess I "used up" the second
> one when I was testing with the windows computer. I don't know why it
> didn't work in the beginning before I began testing with the windows
> computer(maybe because I didn't power cycle the cable modem?), but I'll
> take it !!!!
>
> Thanks for the feedback and the help !!
>
> George
>

Good to here you are up now I had the same problem after I upgraded the
firm ware on my router. I forgot to write down my mac address and I thought
I used my desktop to initially log onto the network. But finally I plugged
in my lap top and got the MAC off that and it instantly logged on.
With using the 2 IPs you should be able to call cox and tell them you got
rid of the one computer so they can clear it off you account and then log
on with whatever you are going to put on it. You might even be able to do
it online for your account.

Dave