Edubuntu in an existing network

[François BARILLON]

I'm trying to install an Edubuntu server on an existing LAN at the aim of demonstration.

Installation : the network card was seen as a wifi (worked fine after fixing manualy the IP)
(/etc/ltsp/dhcpd.conf was fixed in the same way).

First try : the server and a TX linked over a crossed network cable.

I typed "sudo tcpdump -i eth0" to see what was happening :
----
francois at edubuntu:~$ sudo tcpdump -i eth0
tcpdump: verbose output suppressed, use -v or -vv for full protocol
decode
listening on eth0, link-type EN10MB (Ethernet), capture size 96 bytes
12:12:21.438025 IP 0.0.0.0.bootpc > 255.255.255.255.bootps: BOOTP/DHCP,
Request from 00:0c:6e:4a:24:98 (oui Unknown), length: 548

12:12:21.453051 IP 192.168.1.25.32772 > 192.168.1.250.domain:  6886+
PTR? 255.255.255.255.in-addr.arpa. (46)

12:12:23.459483 IP 0.0.0.0.bootpc > 255.255.255.255.bootps: BOOTP/DHCP,
Request from 00:0c:6e:4a:24:98 (oui Unknown), length: 548

12:12:25.107455 IP 192.168.1.25.netbios-dgm > 192.168.1.255.netbios-dgm:
NBT UDP PACKET(138)

12:12:26.451470 arp who-has 192.168.1.250 tell 192.168.1.25

12:12:26.451501 IP 192.168.1.25.32772 > 192.168.1.250.domain:  6886+
PTR? 255.255.255.255.in-addr.arpa. (46)
----
After this messages, the TX is leaving PXE mode.

What can I test to see more?

François