Bogus DHCP Client-ID option (61) results in wrong IP address

Topics about the networking software (ssh, nfs, samba, ...). No questions about network drivers there.
sigprof
Posts: 4
Joined: 11 Apr 2013, 13:54

Bogus DHCP Client-ID option (61) results in wrong IP address

Postby sigprof » 11 Apr 2013, 14:24

In SystemRescueCd >= 3.4.1 (tested also 3.4.2 and 3.5.0) NetworkManager started to send the Client-ID option (code 61) in DHCP discover and request packets:

Code: Select all

17:27:53.287169 00:50:56:06:fc:31 > ff:ff:ff:ff:ff:ff, ethertype IPv4 (0x0800), length 342: (tos 0x10, ttl 128, id 0, offset 0, flags [none], proto UDP (17), length 328)
    0.0.0.0.68 > 255.255.255.255.67: [udp sum ok] BOOTP/DHCP, Request from 00:50:56:06:fc:31, length 300, xid 0x3eb3ba04, Flags [none] (0x0000)
          Client-Ethernet-Address 00:50:56:06:fc:31
          Vendor-rfc1048 Extensions
            Magic Cookie 0x63825363
            DHCP-Message Option 53, length 1: Discover
            Parameter-Request Option 55, length 12:
              Subnet-Mask, BR, Time-Zone, Default-Gateway
              Domain-Name, Domain-Name-Server, Hostname, NTP
              Classless-Static-Route, Classless-Static-Route-Microsoft, Option 252, NTP
            Client-ID Option 61, length 7: ether 00:a0:24:ab:fb:9c
            END Option 255, length 0
            PAD Option 0, length 0, occurs 33
The DHCP server then uses the Ethernet address specified in the Client-ID option when allocating the IP address, and this Client-ID is the same for all machines booting SystemRescueCd; the result is not pretty.

The problem is apparently caused by this line in /etc/dhcp/dhclient.conf:

Code: Select all

#send dhcp-client-identifier 1:0:a0:24:ab:fb:9c;
Yes, this line is commented out, but the broken code in NetworkManager ignores that:
http://cgit.freedesktop.org/NetworkMana ... ils.c#n856

An easy workaround for this problem is to modify /etc/dhcp/dhclient.conf so that it does not contain "send dhcp-client-identifier" (or "send host-name", which is also parsed in the same broken way) even in comments. Could this be fixed in the next SystemRescueCd release?

sigprof
Posts: 4
Joined: 11 Apr 2013, 13:54

Re: Bogus DHCP Client-ID option (61) results in wrong IP add

Postby sigprof » 28 Jun 2013, 13:10

The problem persists in SystemRescueCd 3.7.0 — I still need to edit /etc/dhcp/dhclient.conf and restart NetworkManager to make SystemRescueCd get the correct IP address from the DHCP server.

admin
Site Admin
Posts: 2715
Joined: 17 Jul 2003, 09:44

Re: Bogus DHCP Client-ID option (61) results in wrong IP add

Postby admin » 04 Jul 2013, 18:41

Thanks for your post. This line has been removed in SystemRescueCd-3.7.1-beta004, can you test it ?


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