Problema con l'FTP, il paylod varia in maniera strana

[kurtcobain85na]

Ragazzi salve a tutti, vi spiego il mio problema:
Ho un pc che si connette ad un server della stessa rete per scaricare, tramite FTP, un file di 5GB, a volte ci impiega un ora, altre volte 20 minuti. Utilizzando wireshark ho visto che, nella situazione in cui ci mette un ora, improvvisamente la lunghezza del pacchetto passa da 1448 byte a valori molto inferiori, addirittura 0 byte.
Considerando che la rete è abbastanza complessa non riesco a capire quale sia il motivo, secondo voi quale potrebbe essere il problema? non vi chiedo la soluzione ma solo quali possono essere delle possibili cause.
Sotto potete vedere i tracciamente wireshark

2 0.000001 192.168.169.1 -> 192.168.169.59 TCP edm-adm-notify > 48688 [ACK] Seq=1 Ack=1 Win=65535 Len=1448 TSV=9739 TSER=382631
4 0.000191 192.168.169.1 -> 192.168.169.59 TCP edm-adm-notify > 48688 [ACK] Seq=1449 Ack=1 Win=65535 Len=1448 TSV=9739 TSER=382631
6 0.000194 192.168.169.1 -> 192.168.169.59 TCP edm-adm-notify > 48688 [ACK] Seq=2897 Ack=1 Win=65535 Len=1448 TSV=9739 TSER=382631
8 0.000197 192.168.169.1 -> 192.168.169.59 TCP edm-adm-notify > 48688 [ACK] Seq=4345 Ack=1 Win=65535 Len=1448 TSV=9739 TSER=382631
9 0.000199 192.168.169.1 -> 192.168.169.59 TCP edm-adm-notify > 48688 [PSH, ACK] Seq=5793 Ack=1 Win=65535 Len=376 TSV=9739 TSER=382631
10 0.000200 192.168.169.59 -> 192.168.169.1 TCP 48688 > edm-adm-notify [ACK] Seq=1 Ack=4294939785 Win=3050 Len=0 TSV=382634 TSER=973914 0.001399 192.168.169.59 -> 192.168.169.1 TCP 48688 > edm-adm-notify [ACK] Seq=1 Ack=6169 Win=3050 Len=0 TSV=382635 TSER=9739
19 0.018925 c8:35:b8:29:1e:7e -> ff:ff:ff:ff:ff:ff ARP Who has 192.168.169.59? Tell 192.168.169.1
21 0.018933 c8:35:b8:29:1e:7e -> ff:ff:ff:ff:ff:ff ARP Who has 192.168.169.59? Tell 192.168.169.1
782 0.132255 192.168.169.1 -> 192.168.169.56 SNMP [Packet size limited during capture]
786 0.134187 192.168.169.56 -> 192.168.169.1 SNMP [Packet size limited during capture]
5875 0.959373 192.168.169.33 -> 192.168.169.255 NBDS Direct_group datagram[Packet size limited during capture]
5876 0.959381 192.168.169.33 -> 192.168.169.255 NBDS Direct_group datagram[Packet size limited during capture]
6884 1.099700 192.168.169.59 -> 192.168.169.1 TCP 36881 > 14015 [SYN] Seq=0 Win=5840 Len=0 MSS=1460 TSV=383733 TSER=0 WS=6
6885 1.099702 c8:35:b8:29:1e:7e -> ff:ff:ff:ff:ff:ff ARP Who has 192.168.169.59? Tell 192.168.169.1
6886 1.099707 c8:35:b8:29:1e:7e -> ff:ff:ff:ff:ff:ff ARP Who has 192.168.169.59? Tell 192.168.169.1
8515 1.351662 192.168.169.33 -> 192.168.169.255 NBDS Direct_group datagram[Packet size limited during capture]
8517 1.351671 192.168.169.33 -> 192.168.169.255 NBDS Direct_group datagram[Packet size limited during capture]
9146 1.460125 192.168.169.2 -> 192.168.169.1 DNS Standard query SOA AP75DOM.INT
9147 1.460368 192.168.169.1 -> 192.168.169.2 DNS Standard query response[Packet size limited during capture]
11981 1.928532 192.168.169.1 -> 192.168.169.56 ICMP Echo (ping) request
11982 1.929019 192.168.169.56 -> 192.168.169.1 ICMP Echo (ping) reply
11983 1.929261 192.168.169.1 -> 192.168.169.60 ICMP Echo (ping) request
11984 1.929753 192.168.169.60 -> 192.168.169.1 ICMP Echo (ping) reply
13377 2.146928 c8:35:b8:29:1e:7e -> ff:ff:ff:ff:ff:ff ARP Who has 192.168.169.59? Tell 192.168.169.1
13378 2.146934 c8:35:b8:29:1e:7e -> ff:ff:ff:ff:ff:ff ARP Who has 192.168.169.59? Tell 192.168.169.1
20385 3.350049 c8:35:b8:29:1e:7e -> ff:ff:ff:ff:ff:ff ARP Who has 192.168.169.59? Tell 192.168.169.1
20386 3.350054 c8:35:b8:29:1e:7e -> ff:ff:ff:ff:ff:ff ARP Who has 192.168.169.59? Tell 192.168.169.1
20916 3.446357 3c:19:7d:0d:94:10 -> ff:ff:ff:ff:ff:ff ARP Who has 192.168.169.2? Tell 192.168.169.59
20917 3.446365 3c:19:7d:0d:94:10 -> ff:ff:ff:ff:ff:ff ARP Who has 192.168.169.2? Tell 192.168.169.59
20918 3.446367 192.168.169.1 -> 192.168.169.59 TCP edm-adm-notify > 48688 [ACK] Seq=6169 Ack=1 Win=65535 Len=524 TSV=9773 TSER=382635
20919 3.446844 192.168.169.59 -> 192.168.169.1 TCP 48688 > edm-adm-notify [ACK] Seq=1 Ack=6693 Win=3050 Len=0 TSV=386080 TSER=9773
20920 3.446846 192.168.169.1 -> 192.168.169.59 TCP edm-adm-notify > 48688 [ACK] Seq=6693 Ack=1
20921 3.446847 192.168.169.1 -> 192.168.169.59 TCP edm-adm-notify > 48688 [ACK] Seq=7217 Ack=1 Win=65535 Len=524 TSV=9773 TSER=386080[Packet size limited during capture]
20922 3.447574 192.168.169.59 -> 192.168.169.1 TCP 48688 > edm-adm-notify [ACK] Seq=1 Ack=7217 Win=3050 Len=0 TSV=386081 TSER=9773
20923 3.447575 192.168.169.59 -> 192.168.169.1 TCP 48688 > edm-adm-notify [ACK] Seq=1 Ack=7741 Win=3050 Len=0 TSV=386081 TSER=9773
20924 3.447577 192.168.169.1 -> 192.168.169.59 TCP edm-adm-notify > 48688 [ACK] Seq=7741 Ack=1 Win=65535 Len=524 TSV=9773 TSER=386081
20925 3.447579 192.168.169.1 -> 192.168.169.59 TCP edm-adm-notify > 48688 [ACK] Seq=8265 Ack=1 Win=65535 Len=524 TSV=9773 TSER=386081[Packet size limited during capture]
20926 3.448061 192.168.169.59 -> 192.168.169.1 TCP 48688 > edm-adm-notify [ACK] Seq=1 Ack=8265 Win=3050 Len=0 TSV=386082 TSER=9773
20927 3.448063 192.168.169.59 -> 192.168.169.1 TCP 48688 > edm-adm-notify [ACK] Seq=1 Ack=8789 Win=3050 Len=0 TSV=386082 TSER=9773
20928 3.448065 192.168.169.1 -> 192.168.169.59 TCP edm-adm-notify > 48688 [ACK] Seq=8789 Ack=1 Win=65535 Len=524 TSV=9773 TSER=386082



grazie a tutti