Syslinux - Mar 2014 - Cannot chain to another PXE server on the same subnet

This is what I'm seeing on my DHCP server:

# tcpdump -i eth0 -vvv -s 1500 '(port 67 or port 68)'
tcpdump: listening on eth0, link-type EN10MB (Ethernet), capture size 1500 bytes
13:24:05.679950 IP (tos 0x0, ttl? 20, id 0, offset 0, flags [none], proto: UDP
(17), length: 576) 0.0.0.0.bootpc > 255.255.255.255.bootps: [udp sum ok]
BOOTP/DHCP, Request from 00:24:54:d9:d4:2f (oui Unknown), length 548, xid
0x55d9d42f, secs 4, Flags [ Broadcast ] (0x8000)
????????? Client-Ethernet-Address 00:24:54:d9:d4:2f (oui Unknown)
????????? Vendor-rfc1048 Extensions
??????????? Magic Cookie 0x63825363
??????????? DHCP-Message Option 53, length 1: Discover
??????????? Parameter-Request Option 55, length 24:
????????????? Subnet-Mask, Time-Zone, Default-Gateway, IEN-Name-Server
????????????? Domain-Name-Server, RL, Hostname, BS
????????????? Domain-Name, SS, RP, EP
????????????? Vendor-Option, Server-ID, Vendor-Class, BF
????????????? Option 128, Option 129, Option 130, Option 131
????????????? Option 132, Option 133, Option 134, Option 135

??????????? MSZ Option 57, length 2: 1260
??????????? GUID Option 97, length 17:
0.0.12.143.150.232.29.178.17.128.0.154.39.8.20.171.64
??????????? ARCH Option 93, length 2: 0
??????????? NDI Option 94, length 3: 1.2.1
??????????? Vendor-Class Option 60, length 32:
"PXEClient:Arch:00000:UNDI:002001"
13:24:05.680362 IP (tos 0x10, ttl? 16, id 0, offset 0, flags [none], proto: UDP
(17), length: 328) 10.215.144.7.bootps > 255.255.255.255.bootpc: [udp sum ok]
BOOTP/DHCP, Reply, length 300, xid 0x55d9d42f, secs 4, Flags [ Broadcast ]
(0x8000)
????????? Your-IP 10.215.145.94
????????? Client-Ethernet-Address 00:24:54:d9:d4:2f (oui Unknown)
????????? Vendor-rfc1048 Extensions
??????????? Magic Cookie 0x63825363
??????????? DHCP-Message Option 53, length 1: Offer
??????????? Server-ID Option 54, length 4: 10.215.144.7
??????????? Lease-Time Option 51, length 4: 86400
??????????? Subnet-Mask Option 1, length 4: 255.255.0.0
??????????? Default-Gateway Option 3, length 4: 10.215.144.91
??????????? Domain-Name-Server Option 6, length 8: 10.215.144.31,10.215.144.35
??????????? Domain-Name Option 15, length 19: "mydomain.org"
13:24:05.690690 IP (tos 0x0, ttl 128, id 9218, offset 0, flags [none], proto:
UDP (17), length: 726) 10.215.144.60.bootps > 255.255.255.255.bootpc: [udp
sum ok] BOOTP/DHCP, Reply, length 698, xid 0x55d9d42f, secs 4, Flags [ Broadcast
] (0x8000)
????????? Server-IP 10.215.144.60
????????? Client-Ethernet-Address 00:24:54:d9:d4:2f (oui Unknown)
????????? sname "INF-VM-DS"
????????? file "Bstrap\X86PC\BStrap.0"
????????? Vendor-rfc1048 Extensions
??????????? Magic Cookie 0x63825363
??????????? BS Option 13, length 2: 46
??????????? DHCP-Message Option 53, length 1: Offer
??????????? Server-ID Option 54, length 4: 10.215.144.60
??????????? Vendor-Class Option 60, length 9: "PXEClient"
??????????? ARCH Option 93, length 2: 0
??????????? GUID Option 97, length 17:
0.0.12.143.150.232.29.178.17.128.0.154.39.8.20.171.64
??????????? Vendor-Option Option 43, length 138:
1.4.224.1.1.3.2.2.222.6.3.2.223.6.4.1.1.5.1.1.6.1.11.8.112.170.170.1.10.215.144.60.0.160.1.10.215.144.60.0.129.1.10.215.144.60.0.161.1.10.215.144.60.0.162.1.10.215.144.60.0.164.1.10.215.144.60.0.165.1.10.215.144.60.0.166.1.10.215.144.60.0.167.1.10.215.144.60.0.168.1.10.215.144.60.0.169.1.10.215.144.60.0.170.1.10.215.144.60.0.171.1.10.215.144.60.0.172.1.10.215.144.60.0.131.1.10.215.144.60.187.187.1.10.215.144.60.255
??????????? Vendor-Option Option 43, length 254:
9.203.0.0.22.78.101.120.116.32.68.101.118.105.99.101.32.40.66.73.79.83.47.69.70.73.41.0.160.12.85.98.117.110.116.117.78.101.116.120.56.54.0.129.8.68.79.83.32.85.78.68.73.0.161.12.72.80.32.100.99.55.56.48.48.83.70.70.0.162.11.68.101.108.108.32.79.112.116.51.54.48.0.164.11.71.88.53.50.48.38.71.88.54.50.48.0.165.22.66.114.111.97.100.78.101.116.88.116.114.101.109.101.32.73.73.32.71.105.103.97.0.166.17.68.101.108.108.79.112.116.71.88.54.48.32.69.49.48.48.98.0.167.14.68.114.97.103.101.114.32.82.84.76.56.49.51.57.0.168.5.108.105.110.117.120.0.170.6.118.109.119.97.114.101.0.171.10.72.80.56.48.48.48.69.83.70.70.0.172.6.68.101.108.108.80.69.0.131.5.87.105.110.80.69.10.46.5.80.114.101.115.115.32.91.70.56.93.32.116.111.32.83.101.108.101.99.116.32.97.32.98.111.111.116.32.111.112.116.105.111.110.58.32.73.78.70.45.86.77.45.68.83.255
??????????? Vendor-Option Option 43, length 11: 71.4.0.0.0.0.224.2.0.0.255
13:24:09.799154 IP (tos 0x0, ttl? 20, id 1, offset 0, flags [none], proto: UDP
(17), length: 576) 0.0.0.0.bootpc > 255.255.255.255.bootps: [udp sum ok]
BOOTP/DHCP, Request from 00:24:54:d9:d4:2f (oui Unknown), length 548, xid
0x55d9d42f, secs 4, Flags [ Broadcast ] (0x8000)
????????? Client-Ethernet-Address 00:24:54:d9:d4:2f (oui Unknown)
????????? Vendor-rfc1048 Extensions
??????????? Magic Cookie 0x63825363
??????????? DHCP-Message Option 53, length 1: Request
??????????? Requested-IP Option 50, length 4: 10.215.145.94
??????????? Parameter-Request Option 55, length 24:
????????????? Subnet-Mask, Time-Zone, Default-Gateway, IEN-Name-Server
????????????? Domain-Name-Server, RL, Hostname, BS
????????????? Domain-Name, SS, RP, EP
????????????? Vendor-Option, Server-ID, Vendor-Class, BF
????????????? Option 128, Option 129, Option 130, Option 131
????????????? Option 132, Option 133, Option 134, Option 135

??????????? MSZ Option 57, length 2: 1260
??????????? Server-ID Option 54, length 4: 10.215.144.7
??????????? GUID Option 97, length 17:
0.0.12.143.150.232.29.178.17.128.0.154.39.8.20.171.64
??????????? ARCH Option 93, length 2: 0
??????????? NDI Option 94, length 3: 1.2.1
??????????? Vendor-Class Option 60, length 32:
"PXEClient:Arch:00000:UNDI:002001"
13:24:09.799481 IP (tos 0x10, ttl? 16, id 0, offset 0, flags [none], proto: UDP
(17), length: 328) 10.215.144.7.bootps > 255.255.255.255.bootpc: [udp sum ok]
BOOTP/DHCP, Reply, length 300, xid 0x55d9d42f, secs 4, Flags [ Broadcast ]
(0x8000)
????????? Your-IP 10.215.145.94
????????? Client-Ethernet-Address 00:24:54:d9:d4:2f (oui Unknown)
????????? Vendor-rfc1048 Extensions
??????????? Magic Cookie 0x63825363
??????????? DHCP-Message Option 53, length 1: ACK
??????????? Server-ID Option 54, length 4: 10.215.144.7
??????????? Lease-Time Option 51, length 4: 86400
??????????? Subnet-Mask Option 1, length 4: 255.255.0.0
??????????? Default-Gateway Option 3, length 4: 10.215.144.91
??????????? Domain-Name-Server Option 6, length 8: 10.215.144.31,10.215.144.35
??????????? Domain-Name Option 15, length 19: "mydomain.org"

So the "filename" for 10.215.144.60 should be correct.

Vieri

On Wed, Mar 5, 2014 at 7:28 AM, Vieri <rentorbuy at yahoo.com> wrote:
> This is what I'm seeing on my DHCP server:
Any chance you could sent that as a pcap file (I'd recommend classic
pcap not pcap-ng and then gzip it to give a little semblance of
integrity checking)?  Feel free to send it to me directly.

Second, I notice the Altiris server specifies _3_ options of code 43,
including one of length 253.  The pack/unpack _should_ handle this but
may split it differently.

-- 
-Gene

----- Original Message -----
From: Gene Cumm <gene.cumm at gmail.com>
> Any chance you could sent that as a pcap file
Will do asap.

Thanks

Vieri

On Wed, 2014-03-05 at 13:18 -0500, Gene Cumm wrote:
> Second, I notice the Altiris server specifies _3_ options of code 43,
> including one of length 253.  The pack/unpack _should_ handle this but
> may split it differently.
That's legal, and treated as if the values had been concatenated.  See
RFC2131, section 4.1, and particularly the second paragraph on page 24.
Unfortunately, a lot of implementations get this wrong.  For example,
some client implementations cannot handle encapsulated vendor options
that span more than once instance of the enclosing option 43.

In this case, it appears that the Altiris server is expecting the client
to process each instance of option 43 separately, rather than
concatenating their payloads and processing the result as if it were a
single option value.  In particular, the server is ending each instance
of option 43 with tag 255 (END).  This has the effect that a correct
client ignores everything after the first END tag(*).  This means the
client sees only the following vendor options:

  1  PXE MTFTP IP address
  2  PXE MTFTP client por
  3  PXE MTFTP server port
  4  PXE MTFTP timeout
  5  PXE MTFTP delay
  6  PXE discovery control
  8  PXE boot server list

The client would _not_ see these options:

  9  PXE boot menu
 10  PXE menu prompt control
 71  PXE boot item
224  private use?  probably altiris-specific


(*) This is actually required; see RFC 2132 section 8.4, which says:

      3) Code 255 (END), if present, signifies the end of the
         encapsulated vendor extensions, not the end of the vendor
         extensions field. If no code 255 is present, then the end of
         the enclosing vendor-specific information field is taken as the
         end of the encapsulated vendor-specific extensions field.


-- Jeff