Sep 17 23:34:45 sflow flow-capture[2678]: ftpdu version not set.
Sep 17 23:34:45 sflow flow-capture[2678]: ftpdu_verify(): src_ip=91.*.*.* failed.

DES-3810-28:admin#show sflow
Command: show sflow

 sFlow Version  : V5
 sFlow Address  : 91.*.*.*
 sFlow State    : Enabled

Name        : flow-tools
Arch        : x86_64
Version     : 0.68.5
Release     : 1.el6
Size        : 2.3 M
Repo        : installed
From repo   : CentALT
Summary     : Tool set for working with NetFlow data
URL         : http://code.google.com/p/flow-tools/
License     : BSD

DES-3810-28:admin#show switch
Command: show switch

Device Type       : DES-3810-28 Fast Ethernet Switch
MAC Address       : 00-22-B0-37-92-00
IP Address        : 91.*.*.* (Manual)
VLAN Name         : default
Subnet Mask       : 255.255.255.248
Default Gateway   : 91.*.*.*
Boot PROM Version : Build 2.00.004
Firmware Version  : Build 2.10.024
Hardware Version  : A1
Firmware Type     : SI
Serial Number     : P4T31A8000702

DES-3810-28:admin#show sflow
Command: show sflow

 sFlow Version  : V5
 sFlow Address  : 91.*.*.*
 sFlow State    : Enabled

DES-3810-28:admin#show sflow analyzer_server
Command: show sflow analyzer_server

 sFlow Analyzer_server Information
 ------------------------------
 Server ID             : 1
 Owner                 : sflow
 Timeout               : Infinite
 Current Countdown Time: Infinite
 Collector Address     : 91.*.*.*
 Collector Port        : 2055
 Max Datagram Size     : 1400

Total Entries: 1

DES-3810-28:admin#show sflow counter_poller
Command: show sflow counter_poller

 Port   Analyzer Server ID   Polling Interval (sec)
 ----   ------------------   -----------------------
 27     1                    20

Total Entries: 1

DES-3810-28:admin#show sflow flow_sampler
Command: show sflow flow_sampler

 Port   Analyzer Server ID   Configured Rate   Active Rate   Max Header Size
 ----   ------------------   ---------------   -----------   ---------------
 27     1                    10                10            256

Total Entries: 1

netflow# tcpdump -n udp port 2056
00:33:20.698553 IP 91.*.*.*.34513 > 91.*.*.*.2056: UDP, length 1464
00:33:20.698564 IP 91.*.*.*.34513 > 91.*.*.*.2056: UDP, length 312
00:33:20.985972 IP 91.*.*.*.34513 > 91.*.*.*.2056: UDP, length 1368
00:33:21.285321 IP 91.*.*.*.34513 > 91.*.*.*.2056: UDP, length 1176
00:33:21.494251 IP 91.*.*.*.34513 > 91.*.*.*.2056: UDP, length 1080
00:33:21.721787 IP 91.*.*.*.34513 > 91.*.*.*.2056: UDP, length 984

netflow# tcpdump -n udp port 2055
tcpdump: verbose output suppressed, use -v or -vv for full protocol decode
listening on de0, link-type EN10MB (Ethernet), capture size 65535 bytes
00:35:11.736579 IP 91.*.*.*.6343 > 91.*.*.*.2055: sFlowv5, IPv4 agent 91.*.*.*, agent-id 1, length 188
00:35:13.716766 IP 91.*.*.*.6343 > 91.*.*.*.2055: sFlowv5, IPv4 agent 91.*.*.*, agent-id 1, length 212
00:35:14.707897 IP 91.*.*.*.6343 > 91.*.*.*.2055: sFlowv5, IPv4 agent 91.*.*.*, agent-id 1, length 168
00:35:16.688110 IP 91.*.*.*.6343 > 91.*.*.*.2055: sFlowv5, IPv4 agent 91.*.*.*, agent-id 1, length 192
^C
4 packets captured
62 packets received by filter
0 packets dropped by kernel