[Gllug] Weird problem with TFTP on new Debian Etch server

[John Winters]

I'm trying to move some domestic services over to a new Etch server. 
All seems OK, except that I'm completely unable to get my diskless 
Mini-ITX box to boot from it.

The problem occurs when the diskless workstation tries to use TFTP to 
fetch pxelinux.0 from the server.  I can see the TFTP request come in 
but the server just seems to ignore it.  Here's a tcpdump trace of the 
non-conversation (tcpdump running on the server, duplo, and the diskless 
workstation being "slave):

duplo:/etc/default# tcpdump host slave
tcpdump: verbose output suppressed, use -v or -vv for full protocol decode
listening on eth0, link-type EN10MB (Ethernet), capture size 96 bytes
12:54:49.822680 arp who-has duplo.home.sinodun.org.uk tell 
slave.home.sinodun.org.uk
12:54:49.822719 arp reply duplo.home.sinodun.org.uk is-at 
00:40:05:a5:fb:8c (oui Unknown)
12:54:49.822815 IP slave.home.sinodun.org.uk.2070 > 
duplo.home.sinodun.org.uk.tftp:  27 RRQ "pxelinux.0" octet tsize 0
12:54:51.849592 IP slave.home.sinodun.org.uk.2071 > 
duplo.home.sinodun.org.uk.tftp:  27 RRQ "pxelinux.0" octet tsize 0
12:54:55.859115 IP slave.home.sinodun.org.uk.2072 > 
duplo.home.sinodun.org.uk.tftp:  27 RRQ "pxelinux.0" octet tsize 0

5 packets captured
5 packets received by filter
0 packets dropped by kernel
duplo:/etc/default#

I've tried this with tftpd-hpa on the server (as used on its 
predecessor) and with atftpd running either from inetd or as a daemon. 
The result is the same in all cases.

The really odd thing is that if I use a tftp client from another 
workstation on the network I can fetch pxelinux.0 from the new server 
just fine.  The only noticeable difference is the tftp options in the 
request.  A request from a command line tftp client looks like this:

Using the HPA tftp client:

13:02:38.603739 IP knight.home.sinodun.org.uk.32803 > 
duplo.home.sinodun.org.uk.tftp:  22 RRQ "pxelinux.0" netascii

Using the atftp client:

13:02:48.596232 IP knight.home.sinodun.org.uk.32804 > 
duplo.home.sinodun.org.uk.tftp:  19 RRQ "pxelinux.0" octet

both of which work just fine and get the file.

Can anyone make any suggestions about why requests from the diskless 
workstation are ignored whilst those from the command line client work?

TIA,
John
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