Win7 Ultimate with a network share exposed for user: ABC Win7 home or work network profiles: 'Turn on network discovery' 'Turn on file and printer sharing' 'Turn on sharing so anyone with network access can read and write files in the Public folders' 'Enable file sharing for devices that use 40- or 56-bit encryption' 'Turn on password protected sharing' 'Allow Windows to manage homegorup connections (recommended)' When I try to access a Win7 network share from another Win7 computer, the user authentication works fine. Using Wireshare, I can see that Win7 to Win7 sharing is using SMB2 protocol. Problem: When I try to access the Win7 share from XP Pro SP3, I get the user/password prompt. Entering that information corrrectly, it fails with the following Wireshark dump: No. Time Source Destination Protocol Info 1 0.000000 192.168.3.130 192.168.3.2 DNS Standard query A <Win7-ComputerName>.localdomain 2 0.000174 192.168.3.130 10.21.80.51 TCP sunclustermgr > netbios-ssn [SYN] Seq=0 Win=64240 Len=0 MSS=1460 SACK_PERM=1 3 0.000730 10.21.80.51 192.168.3.130 TCP netbios-ssn > sunclustermgr [SYN, ACK] Seq=0 Ack=1 Win=64240 Len=0 MSS=1460 4 0.000766 192.168.3.2 192.168.3.130 DNS Standard query response A 10.21.80.51 5 0.000835 192.168.3.130 10.21.80.51 NBSS Session request, to <Win7-ComputerName><20> from <XP-computer-name><00> 6 0.001130 192.168.3.130 10.21.80.51 ICMP Echo (ping) request (id=0x0200, seq(be/le)=2304/9, ttl=32) 7 0.001173 10.21.80.51 192.168.3.130 TCP netbios-ssn > sunclustermgr [ACK] Seq=1 Ack=73 Win=64240 Len=0 8 0.001200 10.21.80.51 192.168.3.130 NBSS Positive session response 9 0.001483 10.21.80.51 192.168.3.130 ICMP Echo (ping) reply (id=0x0200, seq(be/le)=2304/9, ttl=128) 10 0.001506 192.168.3.130 10.21.80.51 SMB Negotiate Protocol Request 11 0.001681 10.21.80.51 192.168.3.130 TCP netbios-ssn > sunclustermgr [ACK] Seq=5 Ack=210 Win=64240 Len=0 12 0.002039 10.21.80.51 192.168.3.130 SMB Negotiate Protocol Response 13 0.002528 192.168.3.130 10.21.80.51 SMB Session Setup AndX Request, NTLMSSP_NEGOTIATE 14 0.002652 10.21.80.51 192.168.3.130 TCP netbios-ssn > sunclustermgr [ACK] Seq=136 Ack=450 Win=64240 Len=0 15 0.003098 10.21.80.51 192.168.3.130 SMB Session Setup AndX Response, NTLMSSP_CHALLENGE, Error: STATUS_MORE_PROCESSING_REQUIRED 16 0.003417 192.168.3.130 10.21.80.51 SMB Session Setup AndX Request, NTLMSSP_AUTH, User: \ 17 0.003566 10.21.80.51 192.168.3.130 TCP netbios-ssn > sunclustermgr [ACK] Seq=536 Ack=724 Win=64240 Len=0 18 0.004173 10.21.80.51 192.168.3.130 SMB Session Setup AndX Response 19 0.004584 192.168.3.130 10.21.80.51 SMB Tree Connect AndX Request, Path: \\<Win7-ComputerName>\IPC$ 20 0.005173 10.21.80.51 192.168.3.130 TCP netbios-ssn > sunclustermgr [ACK] Seq=716 Ack=816 Win=64240 Len=0 21 0.005822 10.21.80.51 192.168.3.130 SMB Tree Connect AndX Response 22 0.006386 192.168.3.130 10.21.80.51 SMB Session Setup AndX Request, NTLMSSP_NEGOTIATE 23 0.006529 10.21.80.51 192.168.3.130 TCP netbios-ssn > sunclustermgr [ACK] Seq=776 Ack=1056 Win=64240 Len=0 24 0.006822 10.21.80.51 192.168.3.130 SMB Session Setup AndX Response, NTLMSSP_CHALLENGE, Error: STATUS_MORE_PROCESSING_REQUIRED 25 0.007063 192.168.3.130 10.21.80.51 SMB Session Setup AndX Request, NTLMSSP_AUTH, User: <XP-computer-name>\<logged-in-username> 26 0.007198 10.21.80.51 192.168.3.130 TCP netbios-ssn > sunclustermgr [ACK] Seq=1176 Ack=1432 Win=64240 Len=0 27 0.007704 10.21.80.51 192.168.3.130 SMB Session Setup AndX Response, Error: STATUS_LOGON_FAILURE 28 0.008824 192.168.3.130 10.21.80.51 TCP rmiactivation > http [SYN] Seq=0 Win=64240 Len=0 MSS=1460 SACK_PERM=1 29 0.107500 10.21.80.51 192.168.3.130 SMB [TCP Retransmission] Session Setup AndX Response, Error: STATUS_LOGON_FAILURE 30 0.107645 192.168.3.130 10.21.80.51 TCP sunclustermgr > netbios-ssn [ACK] Seq=1432 Ack=1215 Win=63026 Len=0 31 1.008773 10.21.80.51 192.168.3.130 TCP http > rmiactivation [RST, ACK] Seq=1 Ack=1 Win=64240 Len=0 32 1.463669 192.168.3.130 10.21.80.51 TCP rmiactivation > http [SYN] Seq=0 Win=64240 Len=0 MSS=1460 SACK_PERM=1 33 2.473824 10.21.80.51 192.168.3.130 TCP http > rmiactivation [RST, ACK] Seq=106274982 Ack=1 Win=64240 Len=0 34 2.885741 192.168.3.130 10.21.80.51 TCP rmiactivation > http [SYN] Seq=0 Win=64240 Len=0 MSS=1460 SACK_PERM=1 35 3.885931 10.21.80.51 192.168.3.130 TCP http > rmiactivation [RST, ACK] Seq=4111572875 Ack=1 Win=64240 Len=0 36 3.903925 192.168.3.130 10.21.80.51 SMB Session Setup AndX Request, NTLMSSP_NEGOTIATE 37 3.904153 10.21.80.51 192.168.3.130 TCP netbios-ssn > sunclustermgr [ACK] Seq=1215 Ack=1672 Win=64240 Len=0 38 3.904615 10.21.80.51 192.168.3.130 SMB Session Setup AndX Response, NTLMSSP_CHALLENGE, Error: STATUS_MORE_PROCESSING_REQUIRED 39 3.904826 192.168.3.130 10.21.80.51 SMB Session Setup AndX Request, NTLMSSP_AUTH, User: <XP-computer-name>\<logged-in-username> 40 3.904959 10.21.80.51 192.168.3.130 TCP netbios-ssn > sunclustermgr [ACK] Seq=1615 Ack=2048 Win=64240 Len=0 41 3.905479 10.21.80.51 192.168.3.130 SMB Session Setup AndX Response, Error: STATUS_LOGON_FAILURE 42 3.906952 192.168.3.130 10.21.80.51 SMB Session Setup AndX Request, NTLMSSP_NEGOTIATE 43 3.907094 10.21.80.51 192.168.3.130 TCP netbios-ssn > sunclustermgr [ACK] Seq=1654 Ack=2288 Win=64240 Len=0 44 3.907362 10.21.80.51 192.168.3.130 SMB Session Setup AndX Response, NTLMSSP_CHALLENGE, Error: STATUS_MORE_PROCESSING_REQUIRED 45 3.907724 192.168.3.130 10.21.80.51 SMB Session Setup AndX Request, NTLMSSP_AUTH, User: <XP-computer-name>\<logged-in-username> 46 3.907928 10.21.80.51 192.168.3.130 TCP netbios-ssn > sunclustermgr [ACK] Seq=2054 Ack=2664 Win=64240 Len=0 47 3.908332 10.21.80.51 192.168.3.130 SMB Session Setup AndX Response, Error: STATUS_LOGON_FAILURE 48 4.007731 10.21.80.51 192.168.3.130 SMB [TCP Retransmission] Session Setup AndX Response, Error: STATUS_LOGON_FAILURE 49 4.007870 192.168.3.130 10.21.80.51 TCP sunclustermgr > netbios-ssn [ACK] Seq=2664 Ack=2093 Win=63762 Len=0 50 10.335947 192.168.3.130 10.21.80.51 SMB Session Setup AndX Request, NTLMSSP_NEGOTIATE 51 10.336209 10.21.80.51 192.168.3.130 TCP netbios-ssn > sunclustermgr [ACK] Seq=2093 Ack=2904 Win=64240 Len=0 52 10.336630 10.21.80.51 192.168.3.130 SMB Session Setup AndX Response, NTLMSSP_CHALLENGE, Error: STATUS_MORE_PROCESSING_REQUIRED 53 10.336814 192.168.3.130 10.21.80.51 SMB Session Setup AndX Request, NTLMSSP_AUTH, User: <Win7-ComputerName>\<Win7-acct-name> 54 10.336938 10.21.80.51 192.168.3.130 TCP netbios-ssn > sunclustermgr [ACK] Seq=2493 Ack=3266 Win=64240 Len=0 55 10.337855 10.21.80.51 192.168.3.130 SMB Session Setup AndX Response, Error: STATUS_LOGON_FAILURE 56 10.437089 10.21.80.51 192.168.3.130 SMB [TCP Retransmission] Session Setup AndX Response, Error: STATUS_LOGON_FAILURE 57 10.437234 192.168.3.130 10.21.80.51 TCP sunclustermgr > netbios-ssn [ACK] Seq=3266 Ack=2532 Win=63323 Len=0 58 11.370353 192.168.3.130 10.21.80.51 SMB Logoff AndX Request 59 11.370603 10.21.80.51 192.168.3.130 TCP netbios-ssn > sunclustermgr [ACK] Seq=2532 Ack=3309 Win=64240 Len=0 60 11.370790 192.168.3.130 10.21.80.51 SMB Tree Disconnect Request 61 11.370922 10.21.80.51 192.168.3.130 TCP netbios-ssn > sunclustermgr [ACK] Seq=2532 Ack=3348 Win=64240 Len=0 62 11.370955 10.21.80.51 192.168.3.130 SMB Logoff AndX Response 63 11.371330 10.21.80.51 192.168.3.130 SMB Tree Disconnect Response 64 11.371435 192.168.3.130 10.21.80.51 TCP sunclustermgr > netbios-ssn [ACK] Seq=3348 Ack=2614 Win=63241 Len=0 65 11.371535 192.168.3.130 10.21.80.51 TCP sunclustermgr > netbios-ssn [FIN, ACK] Seq=3348 Ack=2614 Win=63241 Len=0 66 11.371680 10.21.80.51 192.168.3.130 TCP netbios-ssn > sunclustermgr [ACK] Seq=2614 Ack=3349 Win=64239 Len=0 67 11.371756 10.21.80.51 192.168.3.130 TCP netbios-ssn > sunclustermgr [FIN, PSH, ACK] Seq=2614 Ack=3349 Win=64239 Len=0 68 11.371819 192.168.3.130 10.21.80.51 TCP sunclustermgr > netbios-ssn [ACK] Seq=3349 Ack=2615 Win=63241 Len=0 69 14.090122 192.168.3.130 192.168.3.2 DNS Standard query A <Win7-ComputerName>.localdomain 70 14.090400 192.168.3.130 10.21.80.51 TCP mctp > netbios-ssn [SYN] Seq=0 Win=64240 Len=0 MSS=1460 SACK_PERM=1 71 14.090832 192.168.3.2 192.168.3.130 DNS Standard query response A 10.21.80.51 72 14.090908 10.21.80.51 192.168.3.130 TCP netbios-ssn > mctp [SYN, ACK] Seq=0 Ack=1 Win=64240 Len=0 MSS=1460 73 14.090993 192.168.3.130 10.21.80.51 NBSS Session request, to <Win7-ComputerName><20> from <XP-computer-name><00> 74 14.091345 192.168.3.130 10.21.80.51 ICMP Echo (ping) request (id=0x0200, seq(be/le)=2560/10, ttl=32) 75 14.091458 10.21.80.51 192.168.3.130 TCP netbios-ssn > mctp [ACK] Seq=1 Ack=73 Win=64240 Len=0 76 14.091492 10.21.80.51 192.168.3.130 NBSS Positive session response 77 14.091730 192.168.3.130 10.21.80.51 SMB Negotiate Protocol Request 78 14.091802 10.21.80.51 192.168.3.130 ICMP Echo (ping) reply (id=0x0200, seq(be/le)=2560/10, ttl=128) 79 14.091987 10.21.80.51 192.168.3.130 TCP netbios-ssn > mctp [ACK] Seq=5 Ack=210 Win=64240 Len=0 80 14.092388 10.21.80.51 192.168.3.130 SMB Negotiate Protocol Response 81 14.092662 192.168.3.130 10.21.80.51 SMB Session Setup AndX Request, NTLMSSP_NEGOTIATE 82 14.092787 10.21.80.51 192.168.3.130 TCP netbios-ssn > mctp [ACK] Seq=136 Ack=450 Win=64240 Len=0 83 14.093140 10.21.80.51 192.168.3.130 SMB Session Setup AndX Response, NTLMSSP_CHALLENGE, Error: STATUS_MORE_PROCESSING_REQUIRED 84 14.093313 192.168.3.130 10.21.80.51 SMB Session Setup AndX Request, NTLMSSP_AUTH, User: \ 85 14.093430 10.21.80.51 192.168.3.130 TCP netbios-ssn > mctp [ACK] Seq=536 Ack=724 Win=64240 Len=0 86 14.093945 10.21.80.51 192.168.3.130 SMB Session Setup AndX Response 87 14.094203 192.168.3.130 10.21.80.51 SMB Tree Connect AndX Request, Path: \\<Win7-ComputerName>\IPC$ 88 14.094781 10.21.80.51 192.168.3.130 TCP netbios-ssn > mctp [ACK] Seq=716 Ack=816 Win=64240 Len=0 89 14.095367 10.21.80.51 192.168.3.130 SMB Tree Connect AndX Response 90 14.096063 192.168.3.130 10.21.80.51 SMB Session Setup AndX Request, NTLMSSP_NEGOTIATE 91 14.096201 10.21.80.51 192.168.3.130 TCP netbios-ssn > mctp [ACK] Seq=776 Ack=1056 Win=64240 Len=0 92 14.096486 10.21.80.51 192.168.3.130 SMB Session Setup AndX Response, NTLMSSP_CHALLENGE, Error: STATUS_MORE_PROCESSING_REQUIRED 93 14.096713 192.168.3.130 10.21.80.51 SMB Session Setup AndX Request, NTLMSSP_AUTH, User: <XP-computer-name>\<logged-in-username> 94 14.096831 10.21.80.51 192.168.3.130 TCP netbios-ssn > mctp [ACK] Seq=1176 Ack=1432 Win=64240 Len=0 95 14.097414 10.21.80.51 192.168.3.130 SMB Session Setup AndX Response, Error: STATUS_LOGON_FAILURE 96 14.197310 10.21.80.51 192.168.3.130 SMB [TCP Retransmission] Session Setup AndX Response, Error: STATUS_LOGON_FAILURE 97 14.197432 192.168.3.130 10.21.80.51 TCP mctp > netbios-ssn [ACK] Seq=1432 Ack=1215 Win=63026 Len=0 Any help in figuring this out would be greatly appreciated. Jim