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View Full Version : [ubuntu] Problema XDMCP

andrew1988
12-12-2008, 16:15
Ho configurato il mio notebook per un login remoto via xdmcp, ma quando da un altro pc connesso in lan tento di connettermi inserisco l'IP del notebook, lo trova (dicendo anche la versione del kernel..), connetto e compare una schermata nera con una X (nera con bordo bianco) come puntatore senza chiedermi un login.... l'unico modo e' ctrl+alt+backspace x tornare al menu' d login locale.... sbaglio a settare qualcosa sul server?? come lo risolvo sto problemino stupido???
sacarde
13-12-2008, 08:34
riguarda la configurazione di xdmcp


...
...
Per ragioni di sicurezza, X Display Manager Control Protocol è configurato di default (come impostazione predefinita) per rifiutare le connessioni remote delle workstation. Questa è, in genere, la causa del comune problema di vedere soltanto una schermata nera con una cursore a forma di X
...
...
andrew1988
13-12-2008, 12:37
esatto.. infatti io in login windows preferences ho settato
--nel tab remote style: same as local;
--in security ho attivato: allow local system admin login, allow remote system admin login, enable debug...;
--nel tab users ho incluso il mio account e uno creato apposta x il remoto e in escludi ho lasciato nobody;

ho poi osservato che quella X compare anche durante una normale accensione, prima che appaia la schermata d login (welcome theme x intenderci), per circa mezzo secondo..

ho appena provato a includere la porta 177 nelle policy d allow d firestarter.. ma uguale a prima..
:confused:
andrew1988
13-12-2008, 13:02
ho appena analizzato le connessioni XDMCP nel notebook con wireshark e si presenta la situazione del tipo... il client fa la request, server accetta, e il client va in stato di manage continuo... d seguito il codice

No. Time Source Destination Protocol Info
3 27.491127 192.168.1.7 192.168.1.255 XDMCP Broadcast_query

Frame 3 (60 bytes on wire, 60 bytes captured)
Ethernet II, Src: AsustekC_be:ae:ed (00:17:31:be:ae:ed), Dst: Broadcast (ff:ff:ff:ff:ff:ff)
Internet Protocol, Src: 192.168.1.7 (192.168.1.7), Dst: 192.168.1.255 (192.168.1.255)
User Datagram Protocol, Src Port: 53323 (53323), Dst Port: xdmcp (177)
Source port: 53323 (53323)
Destination port: xdmcp (177)
Length: 16
Checksum: 0xaa77 [correct]
[Good Checksum: True]

X Display Manager Control Protocol

No. Time Source Destination Protocol Info
4 29.490667 192.168.1.7 192.168.1.255 XDMCP Broadcast_query

Frame 4 (60 bytes on wire, 60 bytes captured)
Ethernet II, Src: AsustekC_be:ae:ed (00:17:31:be:ae:ed), Dst: Broadcast (ff:ff:ff:ff:ff:ff)
Internet Protocol, Src: 192.168.1.7 (192.168.1.7), Dst: 192.168.1.255 (192.168.1.255)
User Datagram Protocol, Src Port: 53323 (53323), Dst Port: xdmcp (177)
Source port: 53323 (53323)
Destination port: xdmcp (177)
Length: 16
Checksum: 0xaa77 [correct]
[Good Checksum: True]
[Bad Checksum: False]
X Display Manager Control Protocol

No. Time Source Destination Protocol Info
5 31.490806 192.168.1.7 192.168.1.255 XDMCP Broadcast_query

Frame 5 (60 bytes on wire, 60 bytes captured)
Ethernet II, Src: AsustekC_be:ae:ed (00:17:31:be:ae:ed), Dst: Broadcast (ff:ff:ff:ff:ff:ff)
Internet Protocol, Src: 192.168.1.7 (192.168.1.7), Dst: 192.168.1.255 (192.168.1.255)
User Datagram Protocol, Src Port: 53323 (53323), Dst Port: xdmcp (177)
Source port: 53323 (53323)
Destination port: xdmcp (177)
Length: 16
Checksum: 0xaa77 [correct]
[Good Checksum: True]
[Bad Checksum: False]
X Display Manager Control Protocol

No. Time Source Destination Protocol Info
6 32.583571 192.168.1.7 192.168.1.6 XDMCP Query

Frame 6 (60 bytes on wire, 60 bytes captured)
Ethernet II, Src: AsustekC_be:ae:ed (00:17:31:be:ae:ed), Dst: Vmware_9d:26:d4 (00:0c:29:9d:26:d4)
Internet Protocol, Src: 192.168.1.7 (192.168.1.7), Dst: 192.168.1.6 (192.168.1.6)
User Datagram Protocol, Src Port: 53323 (53323), Dst Port: xdmcp (177)
Source port: 53323 (53323)
Destination port: xdmcp (177)
Length: 16
Checksum: 0xab6f [correct]
[Good Checksum: True]
[Bad Checksum: False]
X Display Manager Control Protocol

No. Time Source Destination Protocol Info
9 32.617367 192.168.1.6 192.168.1.7 XDMCP Willing

Frame 9 (90 bytes on wire, 90 bytes captured)
Ethernet II, Src: Vmware_9d:26:d4 (00:0c:29:9d:26:d4), Dst: AsustekC_be:ae:ed (00:17:31:be:ae:ed)
Internet Protocol, Src: 192.168.1.6 (192.168.1.6), Dst: 192.168.1.7 (192.168.1.7)
User Datagram Protocol, Src Port: xdmcp (177), Dst Port: 53323 (53323)
Source port: xdmcp (177)
Destination port: 53323 (53323)
Length: 56
[B]Checksum: 0x83a7 [incorrect, should be 0xb559 (maybe caused by "UDP checksum offload"?)]
[Good Checksum: False]
[Bad Checksum: True]
X Display Manager Control Protocol

No. Time Source Destination Protocol Info
124 169.596461 192.168.1.7 192.168.1.6 XDMCP Query

Frame 124 (60 bytes on wire, 60 bytes captured)
Ethernet II, Src: AsustekC_be:ae:ed (00:17:31:be:ae:ed), Dst: Vmware_9d:26:d4 (00:0c:29:9d:26:d4)
Internet Protocol, Src: 192.168.1.7 (192.168.1.7), Dst: 192.168.1.6 (192.168.1.6)
User Datagram Protocol, Src Port: 60172 (60172), Dst Port: xdmcp (177)
Source port: 60172 (60172)
Destination port: xdmcp (177)
Length: 15
Checksum: 0x90b0 [correct]
[Good Checksum: True]

X Display Manager Control Protocol

No. Time Source Destination Protocol Info
127 169.630098 192.168.1.6 192.168.1.7 XDMCP Willing

Frame 127 (90 bytes on wire, 90 bytes captured)
Ethernet II, Src: Vmware_9d:26:d4 (00:0c:29:9d:26:d4), Dst: AsustekC_be:ae:ed (00:17:31:be:ae:ed)
Internet Protocol, Src: 192.168.1.6 (192.168.1.6), Dst: 192.168.1.7 (192.168.1.7)
User Datagram Protocol, Src Port: xdmcp (177), Dst Port: 60172 (60172)
Source port: xdmcp (177)
Destination port: 60172 (60172)
Length: 56
[B]Checksum: 0x83a7 [incorrect, should be 0x9a98 (maybe caused by "UDP checksum offload"?)]
[Good Checksum: False]
[Bad Checksum: True]
X Display Manager Control Protocol

No. Time Source Destination Protocol Info
128 170.003618 192.168.1.7 192.168.1.6 XDMCP Request

Frame 128 (139 bytes on wire, 139 bytes captured)
Ethernet II, Src: AsustekC_be:ae:ed (00:17:31:be:ae:ed), Dst: Vmware_9d:26:d4 (00:0c:29:9d:26:d4)
Internet Protocol, Src: 192.168.1.7 (192.168.1.7), Dst: 192.168.1.6 (192.168.1.6)
User Datagram Protocol, Src Port: 60172 (60172), Dst Port: xdmcp (177)
Source port: 60172 (60172)
Destination port: xdmcp (177)
Length: 105
Checksum: 0x8735 [correct]
[Good Checksum: True]

X Display Manager Control Protocol

No. Time Source Destination Protocol Info
129 170.010948 192.168.1.6 192.168.1.7 XDMCP Accept

Frame 129 (94 bytes on wire, 94 bytes captured)
Ethernet II, Src: Vmware_9d:26:d4 (00:0c:29:9d:26:d4), Dst: AsustekC_be:ae:ed (00:17:31:be:ae:ed)
Internet Protocol, Src: 192.168.1.6 (192.168.1.6), Dst: 192.168.1.7 (192.168.1.7)
User Datagram Protocol, Src Port: xdmcp (177), Dst Port: 60172 (60172)
Source port: xdmcp (177)
Destination port: 60172 (60172)
Length: 60
[B]Checksum: 0x83ab [incorrect, should be 0x0631 (maybe caused by "UDP checksum offload"?)]
[Good Checksum: False]
[Bad Checksum: True]
X Display Manager Control Protocol

No. Time Source Destination Protocol Info
130 170.540819 192.168.1.7 192.168.1.6 XDMCP Manage

Frame 130 (71 bytes on wire, 71 bytes captured)
Ethernet II, Src: AsustekC_be:ae:ed (00:17:31:be:ae:ed), Dst: Vmware_9d:26:d4 (00:0c:29:9d:26:d4)
Internet Protocol, Src: 192.168.1.7 (192.168.1.7), Dst: 192.168.1.6 (192.168.1.6)
User Datagram Protocol, Src Port: 60172 (60172), Dst Port: xdmcp (177)
Source port: 60172 (60172)
Destination port: xdmcp (177)
Length: 37
Checksum: 0x75e8 [correct]
[Good Checksum: True]
[Bad Checksum: False]
X Display Manager Control Protocol

No. Time Source Destination Protocol Info
132 172.544165 192.168.1.7 192.168.1.6 XDMCP Manage

Frame 132 (71 bytes on wire, 71 bytes captured)
Ethernet II, Src: AsustekC_be:ae:ed (00:17:31:be:ae:ed), Dst: Vmware_9d:26:d4 (00:0c:29:9d:26:d4)
Internet Protocol, Src: 192.168.1.7 (192.168.1.7), Dst: 192.168.1.6 (192.168.1.6)
User Datagram Protocol, Src Port: 60172 (60172), Dst Port: xdmcp (177)
Source port: 60172 (60172)
Destination port: xdmcp (177)
Length: 37
Checksum: 0x75e8 [correct]
[Good Checksum: True]
[Bad Checksum: False]
X Display Manager Control Protocol

No. Time Source Destination Protocol Info
137 176.547241 192.168.1.7 192.168.1.6 XDMCP Manage

Frame 137 (71 bytes on wire, 71 bytes captured)
Ethernet II, Src: AsustekC_be:ae:ed (00:17:31:be:ae:ed), Dst: Vmware_9d:26:d4 (00:0c:29:9d:26:d4)
Internet Protocol, Src: 192.168.1.7 (192.168.1.7), Dst: 192.168.1.6 (192.168.1.6)
User Datagram Protocol, Src Port: 60172 (60172), Dst Port: xdmcp (177)
Source port: 60172 (60172)
Destination port: xdmcp (177)
Length: 37
Checksum: 0x75e8 [correct]
[Good Checksum: True]
[Bad Checksum: False]
X Display Manager Control Protocol

No. Time Source Destination Protocol Info
139 184.551232 192.168.1.7 192.168.1.6 XDMCP Manage

Frame 139 (71 bytes on wire, 71 bytes captured)
Ethernet II, Src: AsustekC_be:ae:ed (00:17:31:be:ae:ed), Dst: Vmware_9d:26:d4 (00:0c:29:9d:26:d4)
Internet Protocol, Src: 192.168.1.7 (192.168.1.7), Dst: 192.168.1.6 (192.168.1.6)
User Datagram Protocol, Src Port: 60172 (60172), Dst Port: xdmcp (177)
Source port: 60172 (60172)
Destination port: xdmcp (177)
Length: 37
Checksum: 0x75e8 [correct]
[Good Checksum: True]
[Bad Checksum: False]
X Display Manager Control Protocol

No. Time Source Destination Protocol Info
411 200.556585 192.168.1.7 192.168.1.6 XDMCP Manage

Frame 411 (71 bytes on wire, 71 bytes captured)
Ethernet II, Src: AsustekC_be:ae:ed (00:17:31:be:ae:ed), Dst: Vmware_9d:26:d4 (00:0c:29:9d:26:d4)
Internet Protocol, Src: 192.168.1.7 (192.168.1.7), Dst: 192.168.1.6 (192.168.1.6)
User Datagram Protocol, Src Port: 60172 (60172), Dst Port: xdmcp (177)
Source port: 60172 (60172)
Destination port: xdmcp (177)
Length: 37
Checksum: 0x75e8 [correct]
[Good Checksum: True]
[Bad Checksum: False]
X Display Manager Control Protocol

tutto ok tranne quel cheksum errato.. ma che cmq sembra che nn serva a nulla x nn accettare la connessione... :muro:
xo' se notate nelle varie request d manage l'intervallo d tempo che le separa l'una dall'altra e' a crescita esponenziale.. (2-4-8-16) che se nn ricordo male serve per inviare delle richieste in modo tale da nn accavallare dei segnali in caso d due connessioni contemporanee.. o una roba simile.. correggetemi se sbaglio.
sacarde
13-12-2008, 13:26
che sistemi e che DE usi?
andrew1988
13-12-2008, 13:45
in entrambi ubuntu 8.10 GNOME, nel notebook sn in virtual machine su vmware e il fisso e' installato sul fisico
sacarde
13-12-2008, 16:03
in
/etc/gdm/custom.conf

hai:

[xdmcp]
Enable=true


p.s.
potrebbe essere un problema della virtualizzazione?
prova con un livecd
andrew1988
13-12-2008, 16:55
il file in questione da me e' gdm.conf-costum ed e' il seguente:



[daemon]

TimedLoginEnable=true
RemoteGreeter=/usr/lib/gdm/gdmgreeter

[security]

AllowRemoteRoot=true
AllowRoot=true
CheckDirOwner=false

[xdmcp]

Enable=true

[gui]

[greeter]

Use24Clock=true
UseInvisibleInEntry=true
IncludeAll=false
Include=remote,andrea

[chooser]

[debug]

Enable=true

[servers]

dunque nn e' quello il problema...
x la virtualizzazione nn penso manco quello.. la connessione e' bridged x cui come ip ho uno della stessa subnet.. cioe'.. nn e' che questa sia una cosa che m serva.. ma m scoccia nn riuscire in un'operazione apparentemente facile come un login remoto..:mad:
sacarde
13-12-2008, 17:03
io e' nelle difficolta' che imparo qualcosa
andrew1988
15-12-2008, 10:58
:help: ...aiuto...:help:
sacarde
15-12-2008, 16:02
http://ubuntrucchi.wordpress.com/2008/04/06/accedere-ad-un-altro-sistema-linux/
andrew1988
15-12-2008, 19:06
gia... seguito il tutorial pari pari ma il problema persevera...
sacarde
15-12-2008, 19:51
qualche connessione funziona?

- ssh (con forward X11)
- vnc

?
andrew1988
15-12-2008, 20:20
funziona?? :D
vnc si funziona
samba si
ftp si
ssh.... nn saprei neanche come testarla

che hai in mente x farmi tale domanda??? :mbe:
sacarde
15-12-2008, 20:37
i log controllati?


p.s.
non mi ricordo se sul server , X deve stare attivo o no
andrew1988
15-12-2008, 20:38
nn capisco il motivo.. ma ho provato a condividere ora una cartella ul pc e cercare d accedervi dal notebook con smb... ma nn trova gli host...e cio succede in entrambe le direzioni........................... :eek: :eek: :eek:
ma si pingano!!!
andrew1988
15-12-2008, 21:38
sacarde!!... ho scoperto quel'e' il problema.. e' il pc!!! con un altro si connette senza problemi in xdmcp..................................................................................

:muro: :muro: :muro: :muro: :muro: :muro: :muro: :muro:

detto cio moderatori chiudete pure questo topic inutile..!!

e grazie della pazienza.... :inchino: