SNMP limit the output strings

Please HELP!

I configured SNMP on esxi 5.1

#esxcli system snmp set -c public

#esxcli system snmp set -t ip-addr/public

#esxcli system snmp set -e true

Sapwalk2.exe -i 192.168.0.1 -c public -v v1 -s 1.3.6.1.2.1 -t 2000 -r 1

sapwalker get result but only ~500 strings

after that i see the message "Device not responding"

if try

Sapwalk2.exe -i 192.168.0.1 -c public -v v1 -s 1.3.6.1.4.1 -t 2000 -r 1

all is fine

i think that the output stops by anti ddos shield

try

SnmpWalk.exe -r:192.168.0.1 -c:public -os:1.3.6.1.2.1.25.1.1 -op:1.3.6.1.2.1.25.2.3

get

OID=.1.3.6.1.2.1.25.1.1.0, Type=TimeTicks, Value=6 days, 21:00:31.00
OID=.1.3.6.1.2.1.25.1.2.0, Type=OctetString, Value=  07 DD 08 0C 04 15 27 00                           
OID=.1.3.6.1.2.1.25.1.3.0, Type=Integer, Value=77
OID=.1.3.6.1.2.1.25.1.4.0, Type=OctetString, Value=/useropts.gz vmbTrustedBoot=false tboot=0x0x101a000 no-auto-partition bootUUID=7085493b87361f57d07ae75d83de8730
OID=.1.3.6.1.2.1.25.1.5.0, Type=Gauge32, Value=0
OID=.1.3.6.1.2.1.25.1.6.0, Type=Gauge32, Value=58
OID=.1.3.6.1.2.1.25.1.7.0, Type=Integer, Value=0
OID=.1.3.6.1.2.1.25.2.2.0, Type=Integer, Value=100627780
%Failed to get value of SNMP variable. Timeout.
Total: 8

/var/log/syslog.log

2013-08-12T05:26:01Z snmpd: lookup_vswitch: fetch VSI_MODULE_NODE_PortCfgs failed Not found

it's something else

anyone has any idea?