| 1 | Server:213.239.210.249
|
|---|
| 2 | Client:192.168.1.155
|
|---|
| 3 | File concern:winscp418setup.exe
|
|---|
| 4 |
|
|---|
| 5 |
|
|---|
| 6 | * step 1: paquets 1-28, creation of SOCKET1
|
|---|
| 7 | * step 2: paquet 29, client send "PASV" command
|
|---|
| 8 | * step 3: paquet 30, server response with ip address and port (here:213.239.210.249:27909)
|
|---|
| 9 | * step 4: paquet 31, client send "LIST" command
|
|---|
| 10 | * step 5: paquet 32, client create a new socket, SOCKET2 with information of step3:Client(1176)-Server(27909)
|
|---|
| 11 | * step 6: paquets 34 and 35, end of creation of socket
|
|---|
| 12 | * step 7: paquet 36, on SOCKET2, server send a result of command "LIST" send in SOCKET1
|
|---|
| 13 | * step 8: paquet 38, immediately, server close SOCKET2
|
|---|
| 14 | * step 9: paquets 39/40 and 44, end of SOCKET2
|
|---|
| 15 | * step 10: paquets 41-43,45-47, on SOCKET1, many FTP command are sent
|
|---|
| 16 | * step 11: paquet 48,FileZilla create a new socket on port 21, SOCKET3 (1177)-Server(21).
|
|---|
| 17 | Socket is create because i drag'n'drop file "winscp418setup.exe" from local workstation to server.
|
|---|
| 18 |
|
|---|
| 19 | On this step, we have 2 SOCKETS for CONNEXION DATA.
|
|---|
| 20 | SOCKET1 Client(1175)-Server(21)
|
|---|
| 21 | SOCKET3 Client(1177)-Server(21)
|
|---|
| 22 | * step 12: paquets 49-57, on SOCKET3, authentification with the same credentials use for SOCKET1
|
|---|
| 23 | * step 13: paquets 58-66, on SOCKET3, many commands are use
|
|---|
| 24 | * step 14: paquet 67, client send PASV command
|
|---|
| 25 | * step 15: paquet 68, server response with ip address and port (here:213.239.210.249:41339)
|
|---|
| 26 | * step 16: paquet 69, client send "STOR" command with name of file
|
|---|
| 27 | * step 17: immediately, client create a new socket, SOCKET4 Client(1179)-Server(41339)
|
|---|
| 28 | * step 18: paquets 71 and 72, end of creation of SOCKET4
|
|---|
| 29 | On this step, we have 3 SOCKETS: 2 for CONNEXION DATA and 1 for command
|
|---|
| 30 | SOCKET1 Client(1175)-Server(21)
|
|---|
| 31 | SOCKET3 Client(1177)-Server(21)
|
|---|
| 32 | SOCKET4 Client(1179)-Server(41339)
|
|---|
| 33 | * step 19: paquets 73-74,77-3319, on SOCKET4, upload of file "winscp418setup.exe"
|
|---|
| 34 |
|
|---|
| 35 | KEEP alive
|
|---|
| 36 | * step 20: paquet 3057, during transfert on "step 19", client send "anti-deconnexion COMMAND"
|
|---|
| 37 | on SOCKET1
|
|---|
| 38 | * step 21: paquet 3064 concern by "keep alive" of SOCKET1, it's confirmation of paquet 3057
|
|---|
| 39 |
|
|---|
| 40 | * step 22: paquet 3320, client send a last segment of file with TCP Flag "FIN" termine upload of file "winscp418setup.exe"
|
|---|
| 41 | * step 23: paquets 3321-3336, server acq a last segment
|
|---|
| 42 | * step 24: paquets 3337, server acq close SOCKET4, it's response of paquet 3320 on step 20
|
|---|
| 43 | * step 25: paquet 3338, client close definitively SOCKET4
|
|---|
| 44 | * step 26: paquet 3339, Server, on SOCKET3, send a command to indicate that "transfert complete"
|
|---|
| 45 | * step 27: paquet 3340, client send "PASV" command
|
|---|
| 46 | * step 28: paquet 3341-3342, server response with ip address and port (here:213.239.210.249:18393)
|
|---|
| 47 |
|
|---|
| 48 | * step 29: paquet 3343, client send "LIST" command on SOCKET3
|
|---|
| 49 | * step 30: paquet 3344, client create a new socket, SOCKET5 with information of step28:Client(1180)-Server(18393)
|
|---|
| 50 | * step 31: paquets 3345 and 3346, end of creation of socket
|
|---|
| 51 | * step 32: paquet 3348, on SOCKET5, server send a result of command "LIST" send in SOCKET3
|
|---|
| 52 | * step 33: paquet 3349, immediately, server close SOCKET4
|
|---|
| 53 | * step 34: paquet 3350, server send a command on SOCKET3
|
|---|
| 54 | * step 35: paquet 3365, correspond when i click on "disconnect". client send a FIN of SOCKET3
|
|---|
| 55 |
|
|---|
| 56 |
|
|---|
| 57 | CONCLUSION
|
|---|
| 58 | Actions to realize:
|
|---|
| 59 | - start FileZilla Client configure with keepAlive
|
|---|
| 60 | - connect to FTP server (Passive mode)
|
|---|
| 61 | - upload a file on server
|
|---|
| 62 | - close file
|
|---|
| 63 |
|
|---|
| 64 | For realize that, FileZilla will create:
|
|---|
| 65 | -2 sockets COMMAND (port 21). With KeepAlive option, FileZilla will on send "KeepAlive" command
|
|---|
| 66 | on one socket
|
|---|
| 67 | -a lot of sockets DATA, in my case, 3.
|
|---|
| 68 |
|
|---|
| 69 | Problem:
|
|---|
| 70 | When i transfert a long file (transfert during 20 minutes for exemple),
|
|---|
| 71 | With Firewall (who manage a timeout in one connexion who is 15mn) between client and Server FTP,
|
|---|
| 72 | one socket in 20 minutes will be kill by the Firewall because no command KEEP-ALIVE is present
|
|---|
| 73 | on this session.
|
|---|
| 74 |
|
|---|
| 75 | The impact
|
|---|
| 76 | FileZilla Client, when receive a RST packet from Firewall for a session who is timeout, he stop
|
|---|
| 77 | ftp transfert and try again. This process slows the copy
|
|---|
| 78 |
|
|---|
| 79 | Solution:
|
|---|
| 80 | Firt solution
|
|---|
| 81 | Use only 2 sockets:
|
|---|
| 82 | - one socket only for command
|
|---|
| 83 | - another socket only for data
|
|---|
| 84 | Second solution
|
|---|
| 85 | - before create a new session of command, close all last sessions command to have just only one
|
|---|
| 86 | session of command
|
|---|
| 87 |
|
|---|
| 88 | I send:
|
|---|
| 89 | - capture realise on my computer
|
|---|
| 90 |
|
|---|
| 91 | I try the others Client FTP and they use
|
|---|
| 92 | will be kill by the firewall
|
|---|
| 93 | FileZilla, to transfert a simple file, use a lot of socket (DATA and
|
|---|
| 94 |
|
|---|
