[SNMP4J] Have some questions regarding to receive response PDU.
Shangkuan chen
adam.inno at gmail.com
Fri Jun 29 16:06:36 CEST 2007
Hi,
I`m new in snmp4j-1.8.2 and I have some questions regarding to receive
response PDU. I'm use PDU's getResponse() methods receive respose PDU ,
but I receive "Null" object. I'm use Ethereal capture packet. I found it
have request and request packet. So, I'm very equivocal it. This is my java
code and Ethereal trace log.
##### It's my code.
public static void main(String[] args) throws IOException {
Address targetAddress = GenericAddress.parse("udp:
192.168.254.254/161");
//Community Target
CommunityTarget target = new CommunityTarget();
target.setCommunity(new OctetString("public"));
target.setAddress(targetAddress);
target.setRetries(3);
target.setTimeout(2000);
// timeout in 2 seconds before a confirmed request is resent or
timed out.
target.setVersion(SnmpConstants.version2c);
// SNMPv1/v2c GETNEXT PDU
PDU pdu = new PDU();
pdu.add(new VariableBinding(new OID(".1.3.6.1.2.1.1.1"))); //
sysDescr
pdu.setType(PDU.GETNEXT);
// dump request PDU
System.out.println(pdu.toString());
Snmp snmp = new Snmp(new DefaultUdpTransportMapping());
ResponseEvent response = snmp.send(pdu, target);
// extract the response PDU (could be null if timed out)
PDU responsePDU = response.getResponse();
if (responsePDU != null){
System.out.println("Received response from: "+
response.getPeerAddress());
// dump response PDU
VariableBinding[] v = responsePDU.toArray();
System.out.println("no. of varbind:" + v.length);
for (int i=0; i<v.length; i++) {
System.out.println(v[i].getVariable().toString());
System.out.println(v[i].getVariable().getSyntaxString());
}
}else{
System.out.println("timed out");
}
}
######### It's a Ethereal trace log
No. Time Source Destination Protocol
Info
2 2.015120 192.168.254.7 192.168.254.254 SNMP
GET-NEXT SNMPv2-MIB::sysDescr
Frame 2 (84 bytes on wire, 84 bytes captured)
Arrival Time: Jun 29, 2007 21:05:38.233249000
Time delta from previous packet: 2.015120000 seconds
Time since reference or first frame: 2.015120000 seconds
Frame Number: 2
Packet Length: 84 bytes
Capture Length: 84 bytes
Protocols in frame: eth:ip:udp:snmp
Coloring Rule Name: UDP
Coloring Rule String: udp
Ethernet II, Src: Wistron_21:9b:44 (00:16:d3:21:9b:44), Dst: Cisco_71:71:b8
(00:0f:23:71:71:b8)
Destination: Cisco_71:71:b8 (00:0f:23:71:71:b8)
Address: Cisco_71:71:b8 (00:0f:23:71:71:b8)
.... ...0 .... .... .... .... = Multicast: This is a UNICAST frame
.... ..0. .... .... .... .... = Locally Administrated Address: This
is a FACTORY DEFAULT address
Source: Wistron_21:9b:44 (00:16:d3:21:9b:44)
Address: Wistron_21:9b:44 (00:16:d3:21:9b:44)
.... ...0 .... .... .... .... = Multicast: This is a UNICAST frame
.... ..0. .... .... .... .... = Locally Administrated Address: This
is a FACTORY DEFAULT address
Type: IP (0x0800)
Internet Protocol, Src: 192.168.254.7 (192.168.254.7), Dst: 192.168.254.254(
192.168.254.254)
Version: 4
Header length: 20 bytes
Differentiated Services Field: 0x00 (DSCP 0x00: Default; ECN: 0x00)
0000 00.. = Differentiated Services Codepoint: Default (0x00)
.... ..0. = ECN-Capable Transport (ECT): 0
.... ...0 = ECN-CE: 0
Total Length: 70
Identification: 0xb9d1 (47569)
Flags: 0x00
0... = Reserved bit: Not set
.0.. = Don't fragment: Not set
..0. = More fragments: Not set
Fragment offset: 0
Time to live: 128
Protocol: UDP (0x11)
Header checksum: 0x027e [correct]
Good: True
Bad : False
Source: 192.168.254.7 (192.168.254.7)
Destination: 192.168.254.254 (192.168.254.254)
User Datagram Protocol, Src Port: 1621 (1621), Dst Port: snmp (161)
Source port: 1621 (1621)
Destination port: snmp (161)
Length: 50
Checksum: 0xd47c [correct]
Simple Network Management Protocol
Version: 2C (1)
Community: public
PDU type: GET-NEXT (1)
Request Id: 0x29f4f1e2
Error Status: NO ERROR (0)
Error Index: 0
Object identifier 1: 1.3.6.1.2.1.1.1 (SNMPv2-MIB::sysDescr)
Value: NULL
No. Time Source Destination Protocol
Info
3 2.022010 192.168.254.254 192.168.254.7 SNMP
RESPONSE SNMPv2-MIB::sysDescr.0
Frame 3 (326 bytes on wire, 326 bytes captured)
Arrival Time: Jun 29, 2007 21:05:38.240139000
Time delta from previous packet: 0.006890000 seconds
Time since reference or first frame: 2.022010000 seconds
Frame Number: 3
Packet Length: 326 bytes
Capture Length: 326 bytes
Protocols in frame: eth:ip:udp:snmp
Coloring Rule Name: UDP
Coloring Rule String: udp
Ethernet II, Src: Cisco_71:71:b8 (00:0f:23:71:71:b8), Dst: Wistron_21:9b:44
(00:16:d3:21:9b:44)
Destination: Wistron_21:9b:44 (00:16:d3:21:9b:44)
Address: Wistron_21:9b:44 (00:16:d3:21:9b:44)
.... ...0 .... .... .... .... = Multicast: This is a UNICAST frame
.... ..0. .... .... .... .... = Locally Administrated Address: This
is a FACTORY DEFAULT address
Source: Cisco_71:71:b8 (00:0f:23:71:71:b8)
Address: Cisco_71:71:b8 (00:0f:23:71:71:b8)
.... ...0 .... .... .... .... = Multicast: This is a UNICAST frame
.... ..0. .... .... .... .... = Locally Administrated Address: This
is a FACTORY DEFAULT address
Type: IP (0x0800)
Internet Protocol, Src: 192.168.254.254 (192.168.254.254), Dst:
192.168.254.7 (192.168.254.7)
Version: 4
Header length: 20 bytes
Differentiated Services Field: 0x00 (DSCP 0x00: Default; ECN: 0x00)
0000 00.. = Differentiated Services Codepoint: Default (0x00)
.... ..0. = ECN-Capable Transport (ECT): 0
.... ...0 = ECN-CE: 0
Total Length: 312
Identification: 0x02b5 (693)
Flags: 0x00
0... = Reserved bit: Not set
.0.. = Don't fragment: Not set
..0. = More fragments: Not set
Fragment offset: 0
Time to live: 255
Protocol: UDP (0x11)
Header checksum: 0x39a8 [correct]
Good: True
Bad : False
Source: 192.168.254.254 (192.168.254.254)
Destination: 192.168.254.7 (192.168.254.7)
User Datagram Protocol, Src Port: snmp (161), Dst Port: 1621 (1621)
Source port: snmp (161)
Destination port: 1621 (1621)
Length: 292
Checksum: 0x984f [correct]
Simple Network Management Protocol
Version: 2C (1)
Community: public
PDU type: RESPONSE (2)
Request Id: 0x29f4f1e2
Error Status: NO ERROR (0)
Error Index: 0
Object identifier 1: 1.3.6.1.2.1.1.1.0 (SNMPv2-MIB::sysDescr.0)
Value: STRING: Cisco IOS Software, C831 Software (C831-K9O3SY6-M),
Version 12.4(1a), RELEASE SOFTWARE (fc2)
Technical Support: http://www.cisco.com/techsupport
Copyright (c) 1986-2005 by Cisco Systems, Inc.
Compiled Fri 27-May-05 23:56
##### End trace log
Can anyone tell me what I am missing here?
Thanks
Adam
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