dhcpcd-discuss

Hi,

I am using ATT U-verse internet service and this company requires to
use their modem (that has DHCP server as well). Model that I use is
2Wire 3600HGV.

I have several machines at home and most of them have no issues with
DHCP. For example my MacBookPro gets dynamic IP without problems. I
have 2 Linux Arch machines as well. And those machines could not
update hostname at server. The logs say (see below) that correct
hostname is sent but the modem shows other (old) name for this
machine. Arch uses dhcpcd 6.0.5 but I saw the same issue with previous
version. I see that other Arch users have the same issue e.g.
https://bbs.archlinux.org/viewtopic.php?pid=1247523

So I am trying to understand whether the problem with Modem, dhcpcd or
something wrong with my new Arch installation.

I ran dhcpdump script that captured request/reply from my Arch box.
See it below. I am a noob in DHCP protocol, maybe someone can make a
quick look and tell me if request looks correct/incorrect.

Another interesting thing is that Modem reports this lease (with old
name) as 'static' although I expect that the machine will get a
dynamic IP as with other machines (e.g. macbook says its address is
dynamic).


Here is log from dhcpdump. The requested hostname is 'boombox' but
modem still uses hostname 'archiso' that it got during installation.


$ sudo dhcpdump -i enp4s0
  TIME: 2013-11-13 06:58:55.118
    IP: 0.0.0.0 (client:machine:mac:address) > 255.255.255.255
(ff:ff:ff:ff:ff:ff)
    OP: 1 (BOOTPREQUEST)
 HTYPE: 1 (Ethernet)
  HLEN: 6
  HOPS: 0
   XID: 2e387f7a
  SECS: 0
 FLAGS: 0
CIADDR: 0.0.0.0
YIADDR: 0.0.0.0
SIADDR: 0.0.0.0
GIADDR: 0.0.0.0
CHADDR: client:machine:mac:address:00:00:00:00:00:00:00:00:00:00
 SNAME: .
 FNAME: .
OPTION:  53 (  1) DHCP message type         3 (DHCPREQUEST)
OPTION:  61 ( 19) Client-identifier
ff:00:00:00:02:00:01:00:01:1a:qq:qq:a2:client:machine:mac:address
OPTION:  50 (  4) Request IP address        192.168.1.89
OPTION:  57 (  2) Maximum DHCP message size 1500
OPTION:  60 ( 52) Vendor class identifier
dhcpcd-6.0.5:Linux-3.11.6-1-ARCH:x86_64:GenuineIntel
OPTION:  12 (  5) Host name                 boombox
OPTION:  55 ( 14) Parameter Request List      1 (Subnet mask)
   121 (Classless Static Route)
    33 (Static route)
     3 (Routers)
     6 (DNS server)
    12 (Host name)
    15 (Domainname)
    28 (Broadcast address)
    42 (NTP servers)
    51 (IP address leasetime)
    54 (Server identifier)
    58 (T1)
    59 (T2)
   119 (Domain Search)

---------------------------------------------------------------------------

  TIME: 2013-11-13 06:58:55.141
    IP: 192.168.1.254 (router:mac:address) > 192.168.1.89
(client:machine:mac:address)
    OP: 2 (BOOTPREPLY)
 HTYPE: 1 (Ethernet)
  HLEN: 6
  HOPS: 0
   XID: 2e387f7a
  SECS: 0
 FLAGS: 0
CIADDR: 0.0.0.0
YIADDR: 192.168.1.89
SIADDR: 192.168.1.254
GIADDR: 0.0.0.0
CHADDR: client:machine:mac:address:00:00:00:00:00:00:00:00:00:00
 SNAME: .
 FNAME: .
OPTION:  53 (  1) DHCP message type         5 (DHCPACK)
OPTION:  54 (  4) Server identifier         192.168.1.254
OPTION:  51 (  4) IP address leasetime      86400 (24h)
OPTION:  58 (  4) T1                        43200 (12h)
OPTION:  59 (  4) T2                        75600 (21h)
OPTION:   6 (  4) DNS server                192.168.1.254
OPTION:   3 (  4) Routers                   192.168.1.254
OPTION:   1 (  4) Subnet mask               255.255.255.0
OPTION:  15 ( 17) Domainname                gateway.2wire.net
---------------------------------------------------------------------------