Wireshark · Wireshark-users: [Wireshark-users] TCP / SMB Broadcast?

[mv652@xxxxxxxxxxxx]

Hi, 

I'd appreciate if someone could take a look at the attached capture of 11 
packets and explain why I am able to see the TCP & SMB negotiation between 
these two hosts. 

My capturing device has IP Address 10.0.4.26 connected on the same switch, 
same VLAN as the two systems in the capture (10.0.4.50 & 10.0.4.6).  The 
capturing system's nic is in promiscious mode. 


Note - I understand why I see the ARP request as it's a broadcast to the 
network address, what I don't understand is why I see the rest of the 
communication between the two.  I even see an ICMP reply from one host to 
the other, but not the original request. 


These systems are running on a managed switch, not a hub. 


Thanks,
Mario 
No.     Time                       Source                Destination           Protocol Info
  23827 2009-07-14 09:16:48.381420 hostname.domainname Broadcast             ARP      Who has 10.0.4.6?  Tell 10.0.4.50

Frame 23827 (60 bytes on wire, 60 bytes captured)
Ethernet II, Src: hostname.domainname (00:18:71:08:a3:1d), Dst: Broadcast (ff:ff:ff:ff:ff:ff)
    Destination: Broadcast (ff:ff:ff:ff:ff:ff)
    Source: hostname.domainname (00:18:71:08:a3:1d)
    Type: ARP (0x0806)
    Trailer: 000000000000000000000000000000000000
Address Resolution Protocol (request)
    Hardware type: Ethernet (0x0001)
    Protocol type: IP (0x0800)
    Hardware size: 6
    Protocol size: 4
    Opcode: request (0x0001)
    Sender MAC address: hostname.domainname (00:18:71:08:a3:1d)
    Sender IP address: hostname.domainname (10.0.4.50)
    Target MAC address: 00:00:00_00:00:00 (00:00:00:00:00:00)
    Target IP address: 10.0.4.6 (10.0.4.6)

No.     Time                       Source                Destination           Protocol Info
  23828 2009-07-14 09:16:48.381431 hostname.domainname 10.0.4.6              ICMP     Echo (ping) reply

Frame 23828 (74 bytes on wire, 74 bytes captured)
Ethernet II, Src: hostname.domainname (00:18:71:08:a3:1d), Dst: Belkin_0a:c5:3a (00:17:3f:0a:c5:3a)
    Destination: Belkin_0a:c5:3a (00:17:3f:0a:c5:3a)
    Source: hostname.domainname (00:18:71:08:a3:1d)
    Type: IP (0x0800)
Internet Protocol, Src: hostname.domainname (10.0.4.50), Dst: 10.0.4.6 (10.0.4.6)
Internet Control Message Protocol
    Type: 0 (Echo (ping) reply)
    Code: 0 ()
    Checksum: 0xc75d [correct]
    Identifier: 0x0200
    Sequence number: 36352 (0x8e00)
    Data (32 bytes)

0000  41 42 43 44 45 46 47 48 49 4a 4b 4c 4d 4e 4f 50   ABCDEFGHIJKLMNOP
0010  51 52 53 54 55 56 57 41 42 43 44 45 46 47 48 49   QRSTUVWABCDEFGHI
        Data: 4142434445464748494A4B4C4D4E4F505152535455565741...

No.     Time                       Source                Destination           Protocol Info
  23829 2009-07-14 09:16:48.381669 hostname.domainname 10.0.4.6              TCP      microsoft-ds > dx-instrument [SYN, ACK] Seq=0 Ack=0 Win=16384 Len=0 MSS=1460

Frame 23829 (62 bytes on wire, 62 bytes captured)
Ethernet II, Src: hostname.domainname (00:18:71:08:a3:1d), Dst: Belkin_0a:c5:3a (00:17:3f:0a:c5:3a)
    Destination: Belkin_0a:c5:3a (00:17:3f:0a:c5:3a)
    Source: hostname.domainname (00:18:71:08:a3:1d)
    Type: IP (0x0800)
Internet Protocol, Src: hostname.domainname (10.0.4.50), Dst: 10.0.4.6 (10.0.4.6)
Transmission Control Protocol, Src Port: microsoft-ds (445), Dst Port: dx-instrument (1325), Seq: 0, Ack: 0, Len: 0
    Source port: microsoft-ds (445)
    Destination port: dx-instrument (1325)
    Sequence number: 0    (relative sequence number)
    Acknowledgement number: 0    (relative ack number)
    Header length: 28 bytes
    Flags: 0x12 (SYN, ACK)
        0... .... = Congestion Window Reduced (CWR): Not set
        .0.. .... = ECN-Echo: Not set
        ..0. .... = Urgent: Not set
        ...1 .... = Acknowledgment: Set
        .... 0... = Push: Not set
        .... .0.. = Reset: Not set
        .... ..1. = Syn: Set
        .... ...0 = Fin: Not set
    Window size: 16384
    Checksum: 0x5178 [correct]
    Options: (8 bytes)
        Maximum segment size: 1460 bytes
        NOP
        NOP
        SACK permitted

No.     Time                       Source                Destination           Protocol Info
  23830 2009-07-14 09:16:48.381670 hostname.domainname 10.0.4.6              ICMP     Echo (ping) reply

Frame 23830 (74 bytes on wire, 74 bytes captured)
Ethernet II, Src: hostname.domainname (00:18:71:08:a3:1d), Dst: Belkin_0a:c5:3a (00:17:3f:0a:c5:3a)
    Destination: Belkin_0a:c5:3a (00:17:3f:0a:c5:3a)
    Source: hostname.domainname (00:18:71:08:a3:1d)
    Type: IP (0x0800)
Internet Protocol, Src: hostname.domainname (10.0.4.50), Dst: 10.0.4.6 (10.0.4.6)
Internet Control Message Protocol
    Type: 0 (Echo (ping) reply)
    Code: 0 ()
    Checksum: 0xc65d [correct]
    Identifier: 0x0200
    Sequence number: 36608 (0x8f00)
    Data (32 bytes)

0000  41 42 43 44 45 46 47 48 49 4a 4b 4c 4d 4e 4f 50   ABCDEFGHIJKLMNOP
0010  51 52 53 54 55 56 57 41 42 43 44 45 46 47 48 49   QRSTUVWABCDEFGHI
        Data: 4142434445464748494A4B4C4D4E4F505152535455565741...

No.     Time                       Source                Destination           Protocol Info
  23831 2009-07-14 09:16:48.381921 hostname.domainname 10.0.4.6              SMB      Negotiate Protocol Response

Frame 23831 (245 bytes on wire, 245 bytes captured)
Ethernet II, Src: hostname.domainname (00:18:71:08:a3:1d), Dst: Belkin_0a:c5:3a (00:17:3f:0a:c5:3a)
    Destination: Belkin_0a:c5:3a (00:17:3f:0a:c5:3a)
    Source: hostname.domainname (00:18:71:08:a3:1d)
    Type: IP (0x0800)
Internet Protocol, Src: hostname.domainname (10.0.4.50), Dst: 10.0.4.6 (10.0.4.6)
Transmission Control Protocol, Src Port: microsoft-ds (445), Dst Port: dx-instrument (1325), Seq: 1, Ack: 137, Len: 191
    Source port: microsoft-ds (445)
    Destination port: dx-instrument (1325)
    Sequence number: 1    (relative sequence number)
    [Next sequence number: 192    (relative sequence number)]
    Acknowledgement number: 137    (relative ack number)
    Header length: 20 bytes
    Flags: 0x18 (PSH, ACK)
        0... .... = Congestion Window Reduced (CWR): Not set
        .0.. .... = ECN-Echo: Not set
        ..0. .... = Urgent: Not set
        ...1 .... = Acknowledgment: Set
        .... 1... = Push: Set
        .... .0.. = Reset: Not set
        .... ..0. = Syn: Not set
        .... ...0 = Fin: Not set
    Window size: 65398
    Checksum: 0x0cc7 [correct]
NetBIOS Session Service
SMB (Server Message Block Protocol)
    SMB Header
    Negotiate Protocol Response (0x72)
        Word Count (WCT): 17
        Dialect Index: 5, greater than LANMAN2.1
        Security Mode: 0x0f
        Max Mpx Count: 50
        Max VCs: 1
        Max Buffer Size: 16644
        Max Raw Buffer: 65536
        Session Key: 0x00000000
        Capabilities: 0x8001f3fd
        System Time: Jul 14, 2009 09:16:51.934035400
        Server Time Zone: -120 min from UTC
        Key Length: 0
        Byte Count (BCC): 118
        Server GUID: 3C728C9B734339428EB1B6E6BEC29EBC
        Security Blob: 606406062B0601050502A05A3058A030302E06092A864882...
            GSS-API Generic Security Service Application Program Interface
                OID: 1.3.6.1.5.5.2 (SPNEGO - Simple Protected Negotiation)
                SPNEGO
                    negTokenInit
                        mechTypes: 4 items
                        mechListMIC: 3022A0201B1E66696C65736572766572244054524144494E...
                            principal: hostname$@domainname

No.     Time                       Source                Destination           Protocol Info
  23832 2009-07-14 09:16:48.382668 hostname.domainname 10.0.4.6              TCP      microsoft-ds > dx-instrument [ACK] Seq=192 Ack=2833 Win=65535 Len=0

Frame 23832 (60 bytes on wire, 60 bytes captured)
Ethernet II, Src: hostname.domainname (00:18:71:08:a3:1d), Dst: Belkin_0a:c5:3a (00:17:3f:0a:c5:3a)
    Destination: Belkin_0a:c5:3a (00:17:3f:0a:c5:3a)
    Source: hostname.domainname (00:18:71:08:a3:1d)
    Type: IP (0x0800)
    Trailer: 000000000000
Internet Protocol, Src: hostname.domainname (10.0.4.50), Dst: 10.0.4.6 (10.0.4.6)
Transmission Control Protocol, Src Port: microsoft-ds (445), Dst Port: dx-instrument (1325), Seq: 192, Ack: 2833, Len: 0
    Source port: microsoft-ds (445)
    Destination port: dx-instrument (1325)
    Sequence number: 192    (relative sequence number)
    Acknowledgement number: 2833    (relative ack number)
    Header length: 20 bytes
    Flags: 0x10 (ACK)
        0... .... = Congestion Window Reduced (CWR): Not set
        .0.. .... = ECN-Echo: Not set
        ..0. .... = Urgent: Not set
        ...1 .... = Acknowledgment: Set
        .... 0... = Push: Not set
        .... .0.. = Reset: Not set
        .... ..0. = Syn: Not set
        .... ...0 = Fin: Not set
    Window size: 65535
    Checksum: 0xb26c [correct]

No.     Time                       Source                Destination           Protocol Info
  23833 2009-07-14 09:16:48.383667 hostname.domainname 10.0.4.6              SMB      Session Setup AndX Response

Frame 23833 (403 bytes on wire, 403 bytes captured)
Ethernet II, Src: hostname.domainname (00:18:71:08:a3:1d), Dst: Belkin_0a:c5:3a (00:17:3f:0a:c5:3a)
    Destination: Belkin_0a:c5:3a (00:17:3f:0a:c5:3a)
    Source: hostname.domainname (00:18:71:08:a3:1d)
    Type: IP (0x0800)
Internet Protocol, Src: hostname.domainname (10.0.4.50), Dst: 10.0.4.6 (10.0.4.6)
Transmission Control Protocol, Src Port: microsoft-ds (445), Dst Port: dx-instrument (1325), Seq: 192, Ack: 2833, Len: 349
    Source port: microsoft-ds (445)
    Destination port: dx-instrument (1325)
    Sequence number: 192    (relative sequence number)
    [Next sequence number: 541    (relative sequence number)]
    Acknowledgement number: 2833    (relative ack number)
    Header length: 20 bytes
    Flags: 0x18 (PSH, ACK)
        0... .... = Congestion Window Reduced (CWR): Not set
        .0.. .... = ECN-Echo: Not set
        ..0. .... = Urgent: Not set
        ...1 .... = Acknowledgment: Set
        .... 1... = Push: Set
        .... .0.. = Reset: Not set
        .... ..0. = Syn: Not set
        .... ...0 = Fin: Not set
    Window size: 65535
    Checksum: 0x7ac4 [correct]
NetBIOS Session Service
SMB (Server Message Block Protocol)
    SMB Header
    Session Setup AndX Response (0x73)
        Word Count (WCT): 4
        AndXCommand: No further commands (0xff)
        Reserved: 00
        AndXOffset: 345
        Action: 0x0000
        Security Blob Length: 162
        Byte Count (BCC): 302
        Security Blob: A1819F30819CA0030A0100A10B06092A864882F712010202...
            GSS-API Generic Security Service Application Program Interface
                SPNEGO
                    negTokenTarg
        Native OS: Windows Server 2003 R2 3790 Service Pack 1
        Native LAN Manager: Windows Server 2003 R2 5.2

No.     Time                       Source                Destination           Protocol Info
  23834 2009-07-14 09:16:48.383917 hostname.domainname 10.0.4.6              SMB      Tree Connect AndX Response

Frame 23834 (114 bytes on wire, 114 bytes captured)
Ethernet II, Src: hostname.domainname (00:18:71:08:a3:1d), Dst: Belkin_0a:c5:3a (00:17:3f:0a:c5:3a)
    Destination: Belkin_0a:c5:3a (00:17:3f:0a:c5:3a)
    Source: hostname.domainname (00:18:71:08:a3:1d)
    Type: IP (0x0800)
Internet Protocol, Src: hostname.domainname (10.0.4.50), Dst: 10.0.4.6 (10.0.4.6)
Transmission Control Protocol, Src Port: microsoft-ds (445), Dst Port: dx-instrument (1325), Seq: 541, Ack: 2961, Len: 60
    Source port: microsoft-ds (445)
    Destination port: dx-instrument (1325)
    Sequence number: 541    (relative sequence number)
    [Next sequence number: 601    (relative sequence number)]
    Acknowledgement number: 2961    (relative ack number)
    Header length: 20 bytes
    Flags: 0x18 (PSH, ACK)
        0... .... = Congestion Window Reduced (CWR): Not set
        .0.. .... = ECN-Echo: Not set
        ..0. .... = Urgent: Not set
        ...1 .... = Acknowledgment: Set
        .... 1... = Push: Set
        .... .0.. = Reset: Not set
        .... ..0. = Syn: Not set
        .... ...0 = Fin: Not set
    Window size: 65407
    Checksum: 0x4e43 [correct]
NetBIOS Session Service
SMB (Server Message Block Protocol)
    SMB Header
    Tree Connect AndX Response (0x75)
        Word Count (WCT): 7
        AndXCommand: No further commands (0xff)
        Reserved: 00
        AndXOffset: 56
        Optional Support: 0x0001
        Word parameter: 0x01ff
        Word parameter: 0x0000
        Word parameter: 0x01ff
        Word parameter: 0x0000
        Byte Count (BCC): 7
        Service: IPC
        Extra byte parameters

No.     Time                       Source                Destination           Protocol Info
  23835 2009-07-14 09:16:48.384417 hostname.domainname 10.0.4.6              SMB      Trans2 Response<unknown>

Frame 23835 (254 bytes on wire, 254 bytes captured)
Ethernet II, Src: hostname.domainname (00:18:71:08:a3:1d), Dst: Belkin_0a:c5:3a (00:17:3f:0a:c5:3a)
    Destination: Belkin_0a:c5:3a (00:17:3f:0a:c5:3a)
    Source: hostname.domainname (00:18:71:08:a3:1d)
    Type: IP (0x0800)
Internet Protocol, Src: hostname.domainname (10.0.4.50), Dst: 10.0.4.6 (10.0.4.6)
Transmission Control Protocol, Src Port: microsoft-ds (445), Dst Port: dx-instrument (1325), Seq: 601, Ack: 3037, Len: 200
    Source port: microsoft-ds (445)
    Destination port: dx-instrument (1325)
    Sequence number: 601    (relative sequence number)
    [Next sequence number: 801    (relative sequence number)]
    Acknowledgement number: 3037    (relative ack number)
    Header length: 20 bytes
    Flags: 0x18 (PSH, ACK)
        0... .... = Congestion Window Reduced (CWR): Not set
        .0.. .... = ECN-Echo: Not set
        ..0. .... = Urgent: Not set
        ...1 .... = Acknowledgment: Set
        .... 1... = Push: Set
        .... .0.. = Reset: Not set
        .... ..0. = Syn: Not set
        .... ...0 = Fin: Not set
    Window size: 65331
    Checksum: 0x1aee [correct]
NetBIOS Session Service
SMB (Server Message Block Protocol)
    SMB Header
    Trans2 Response (0x32)
        Subcommand: <UNKNOWN> since request packet wasn't seen
        Word Count (WCT): 10
        Total Parameter Count: 0
        Total Data Count: 140
        Reserved: 0000
        Parameter Count: 0
        Parameter Offset: 56
        Parameter Displacement: 0
        Data Count: 140
        Data Offset: 56
        Data Displacement: 0
        Setup Count: 0
        Reserved: 00
        Byte Count (BCC): 141
        Padding: 00
        Unknown Transaction2 Data

No.     Time                       Source                Destination           Protocol Info
  23836 2009-07-14 09:16:48.386916 hostname.domainname 10.0.4.6              SMB      Trans2 Response<unknown>

Frame 23836 (258 bytes on wire, 258 bytes captured)
Ethernet II, Src: hostname.domainname (00:18:71:08:a3:1d), Dst: Belkin_0a:c5:3a (00:17:3f:0a:c5:3a)
    Destination: Belkin_0a:c5:3a (00:17:3f:0a:c5:3a)
    Source: hostname.domainname (00:18:71:08:a3:1d)
    Type: IP (0x0800)
Internet Protocol, Src: hostname.domainname (10.0.4.50), Dst: 10.0.4.6 (10.0.4.6)
Transmission Control Protocol, Src Port: microsoft-ds (445), Dst Port: dx-instrument (1325), Seq: 801, Ack: 3151, Len: 204
    Source port: microsoft-ds (445)
    Destination port: dx-instrument (1325)
    Sequence number: 801    (relative sequence number)
    [Next sequence number: 1005    (relative sequence number)]
    Acknowledgement number: 3151    (relative ack number)
    Header length: 20 bytes
    Flags: 0x18 (PSH, ACK)
        0... .... = Congestion Window Reduced (CWR): Not set
        .0.. .... = ECN-Echo: Not set
        ..0. .... = Urgent: Not set
        ...1 .... = Acknowledgment: Set
        .... 1... = Push: Set
        .... .0.. = Reset: Not set
        .... ..0. = Syn: Not set
        .... ...0 = Fin: Not set
    Window size: 65217
    Checksum: 0xb727 [correct]
NetBIOS Session Service
SMB (Server Message Block Protocol)
    SMB Header
    Trans2 Response (0x32)
        Subcommand: <UNKNOWN> since request packet wasn't seen
        Word Count (WCT): 10
        Total Parameter Count: 0
        Total Data Count: 144
        Reserved: 0000
        Parameter Count: 0
        Parameter Offset: 56
        Parameter Displacement: 0
        Data Count: 144
        Data Offset: 56
        Data Displacement: 0
        Setup Count: 0
        Reserved: 00
        Byte Count (BCC): 145
        Padding: 00
        Unknown Transaction2 Data

No.     Time                       Source                Destination           Protocol Info
  23837 2009-07-14 09:16:48.387166 hostname.domainname 10.0.4.6              SMB      Trans2 Response<unknown>

Frame 23837 (204 bytes on wire, 204 bytes captured)
Ethernet II, Src: hostname.domainname (00:18:71:08:a3:1d), Dst: Belkin_0a:c5:3a (00:17:3f:0a:c5:3a)
    Destination: Belkin_0a:c5:3a (00:17:3f:0a:c5:3a)
    Source: hostname.domainname (00:18:71:08:a3:1d)
    Type: IP (0x0800)
Internet Protocol, Src: hostname.domainname (10.0.4.50), Dst: 10.0.4.6 (10.0.4.6)
Transmission Control Protocol, Src Port: microsoft-ds (445), Dst Port: dx-instrument (1325), Seq: 1005, Ack: 3249, Len: 150
    Source port: microsoft-ds (445)
    Destination port: dx-instrument (1325)
    Sequence number: 1005    (relative sequence number)
    [Next sequence number: 1155    (relative sequence number)]
    Acknowledgement number: 3249    (relative ack number)
    Header length: 20 bytes
    Flags: 0x18 (PSH, ACK)
        0... .... = Congestion Window Reduced (CWR): Not set
        .0.. .... = ECN-Echo: Not set
        ..0. .... = Urgent: Not set
        ...1 .... = Acknowledgment: Set
        .... 1... = Push: Set
        .... .0.. = Reset: Not set
        .... ..0. = Syn: Not set
        .... ...0 = Fin: Not set
    Window size: 65119
    Checksum: 0x6518 [correct]
NetBIOS Session Service
SMB (Server Message Block Protocol)
    SMB Header
    Trans2 Response (0x32)
        Subcommand: <UNKNOWN> since request packet wasn't seen
        Word Count (WCT): 10
        Total Parameter Count: 0
        Total Data Count: 90
        Reserved: 0000
        Parameter Count: 0
        Parameter Offset: 56
        Parameter Displacement: 0
        Data Count: 90
        Data Offset: 56
        Data Displacement: 0
        Setup Count: 0
        Reserved: 00
        Byte Count (BCC): 91
        Padding: 00
        Unknown Transaction2 Data