第 7 章網絡監控
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第 7 章網絡監控

7.1. NET SNMP (Simple Network Management Protocol)

7.1.1. 安裝SNMP

7.1.1.1. Ubuntu

search package

netkiller@neo:~$ apt-cache search snmp
libsnmp-base - NET SNMP (Simple Network Management Protocol) MIBs and Docs
libsnmp-perl - NET SNMP (Simple Network Management Protocol) Perl5 Support
libsnmp-session-perl - Perl support for accessing SNMP-aware devices
libsnmp9 - NET SNMP (Simple Network Management Protocol) Library
libsnmp9-dev - NET SNMP (Simple Network Management Protocol) Development Files
snmp - NET SNMP (Simple Network Management Protocol) Apps
snmpd - NET SNMP (Simple Network Management Protocol) Agents
php5-snmp - SNMP module for php5
tcpdump - A powerful tool for network monitoring and data acquisition

安裝

netkiller@neo:~$ sudo apt-get install snmp snmpd

7.1.1.1.1. snmpd.conf

配置 /etc/snmp/snmpd.conf

配置agentAddress

agentAddress  udp:172.16.1.3:161

#       sec.name  source          community
com2sec paranoid  default          chen

#           incl/excl subtree                          mask
view all    included  .1                               80
view system included  .iso.org.dod.internet.mgmt.mib-2.system
view system included  .iso.org.dod.internet.mgmt.mib-2.host
view system included  .iso.org.dod.internet.mgmt.mib-2.interfaces

.iso.org.dod.internet.mgmt.mib-2.host 可以使用命令 snmptranslate -Onf -IR hrStorageDescr得到

參考:http://www.mkssoftware.com/docs/man1/snmptranslate.1.asp

7.1.1.1.2. SNMP v3

neo@debian:~$ sudo /etc/init.d/snmpd stop
Stopping network management services: snmpd snmptrapd.

neo@debian:~$ sudo net-snmp-config --create-snmpv3-user -ro -a "netadminpassword" netadmin
adding the following line to /var/lib/snmp/snmpd.conf:
   createUser netadmin MD5 "netadminpassword" DES
adding the following line to /usr/share/snmp/snmpd.conf:
   rouser netadmin

neo@debian:~$ sudo /etc/init.d/snmpd start
Starting network management services: snmpd.

test

				
neo@debian:~$ snmpget -v 3 -u netadmin -l authNoPriv -a MD5 -A <passwd> 127.0.0.1 sysUpTime.0
DISMAN-EVENT-MIB::sysUpTimeInstance = Timeticks: (6342) 0:01:03.42

With a different password this fails:

neo@debian:~$ snmpget -v 3 -u netadmin -l authNoPriv -a MD5 -A nopasswd 127.0.0.1 sysUpTime.0
snmpget: Authentication failure (incorrect password, community or key) (Sub-id not found: (top) -> sysUpTime)

Note that this can be stuck in a snmp.conf file in ~/.snmp:

				
neo@debian:~$ mkdir ~/.snmp
neo@debian:~$ vim ~/.snmp/snmp.conf
defSecurityName netadmin
defContext ""
defAuthType MD5
defSecurityLevel authNoPriv
defAuthPassphrase <netadminpassword>
defVersion 3

test

neo@debian:~$ snmpget 127.0.0.1 sysUpTime.0
DISMAN-EVENT-MIB::sysUpTimeInstance = Timeticks: (39471) 0:06:34.71

7.1.1.2. CentOS

			
yum install net-snmp -y

cp /etc/snmp/snmpd.conf{,.original}

vim /etc/snmp/snmpd.conf <<VIM > /dev/null 2>&1
:62,62s/systemview/all/
:85,85s/^#//
:162,162s/syslocation Unknown/syslocation Neo/
:163,163s/syscontact Root <root@localhost>/syscontact Neo <netkiller@msn.com>/
:wq
VIM

service snmpd start
chkconfig snmpd on

7.1.1.2.1. Configure SNMPv3 on CentOS or RHEL

# yum install net-snmp-utils net-snmp-devel
# service snmpd stop
# net-snmp-create-v3-user -ro -A snmpv3pass -a MD5 -x DES snmpv3user
# service snmpd start

Test SNMPv3

# snmpwalk -u snmpv3user -A snmpv3pass -a MD5 -l authnoPriv 192.168.1.2 -v3

7.1.2. 配置SNMP

7.1.2.1. community 配置

預設為 public, 版本支持v1與v2c, 只讀權限

#       sec.name  source          community
com2sec notConfigUser  default       public

#       groupName      securityModel securityName
group   notConfigGroup v1           notConfigUser
group   notConfigGroup v2c           notConfigUser

#       group          context sec.model sec.level prefix read   write  notif
access  notConfigGroup ""      any       noauth    exact  systemview none none

現在我們新增一個 community

7.1.2.2. 定義可操作的範圍

下面我們定義一個最大可操作範圍用於Cacti監控

#access  notConfigGroup ""      any       noauth    exact  systemview none none
access  notConfigGroup ""      any       noauth    exact  all none none

#       name           incl/excl     subtree         mask(optional)
view all    included  .1                               80

A variable list

name: 預設是 systemview 這裡使用all
incl/excl: 是包含于排除
subtree: 視圖中涉及的MIB子樹
mask(optional): 掩碼

7.1.3. SNMP 命令

7.1.3.1. snmpwalk

$ snmpwalk -c public -v2c 172.16.1.10 hrSWRunPerfMem | awk 'BEGIN {total_mem=0} { if ($NF == "KBytes") {total_mem=total_mem+$(NF-1)}}  END {print total_mem}'
655784

$ snmpwalk -c public -v 1 127.0.0.1 1.3.6.1.2.1.1

			
netkiller@neo:/etc/snmp$ snmpwalk -c public -v 1 127.0.0.1 1.3.6.1.2.1.1
SNMPv2-MIB::sysDescr.0 = STRING: Linux neo.example.org 2.6.17-10-server #2 SMP Tue Dec 5 22:29:32 UTC 2006 i686
SNMPv2-MIB::sysObjectID.0 = OID: NET-SNMP-MIB::netSnmpAgentOIDs.10
DISMAN-EVENT-MIB::sysUpTimeInstance = Timeticks: (120146) 0:20:01.46
SNMPv2-MIB::sysContact.0 = STRING: Root <root@localhost> (configure /etc/snmp/snmpd.local.conf)
SNMPv2-MIB::sysName.0 = STRING: neo.example.org
SNMPv2-MIB::sysLocation.0 = STRING: Unknown (configure /etc/snmp/snmpd.local.conf)
SNMPv2-MIB::sysORLastChange.0 = Timeticks: (18) 0:00:00.18
SNMPv2-MIB::sysORID.1 = OID: IF-MIB::ifMIB
SNMPv2-MIB::sysORID.2 = OID: SNMPv2-MIB::snmpMIB
SNMPv2-MIB::sysORID.3 = OID: TCP-MIB::tcpMIB
SNMPv2-MIB::sysORID.4 = OID: IP-MIB::ip
SNMPv2-MIB::sysORID.5 = OID: UDP-MIB::udpMIB
SNMPv2-MIB::sysORID.6 = OID: SNMP-VIEW-BASED-ACM-MIB::vacmBasicGroup
SNMPv2-MIB::sysORID.7 = OID: SNMP-FRAMEWORK-MIB::snmpFrameworkMIBCompliance
SNMPv2-MIB::sysORID.8 = OID: SNMP-MPD-MIB::snmpMPDCompliance
SNMPv2-MIB::sysORID.9 = OID: SNMP-USER-BASED-SM-MIB::usmMIBCompliance
SNMPv2-MIB::sysORDescr.1 = STRING: The MIB module to describe generic objects for network interface sub-layers
SNMPv2-MIB::sysORDescr.2 = STRING: The MIB module for SNMPv2 entities
SNMPv2-MIB::sysORDescr.3 = STRING: The MIB module for managing TCP implementations
SNMPv2-MIB::sysORDescr.4 = STRING: The MIB module for managing IP and ICMP implementations
SNMPv2-MIB::sysORDescr.5 = STRING: The MIB module for managing UDP implementations
SNMPv2-MIB::sysORDescr.6 = STRING: View-based Access Control Model for SNMP.
SNMPv2-MIB::sysORDescr.7 = STRING: The SNMP Management Architecture MIB.
SNMPv2-MIB::sysORDescr.8 = STRING: The MIB for Message Processing and Dispatching.
SNMPv2-MIB::sysORDescr.9 = STRING: The management information definitions for the SNMP User-based Security Model.
SNMPv2-MIB::sysORUpTime.1 = Timeticks: (12) 0:00:00.12
SNMPv2-MIB::sysORUpTime.2 = Timeticks: (12) 0:00:00.12
SNMPv2-MIB::sysORUpTime.3 = Timeticks: (12) 0:00:00.12
SNMPv2-MIB::sysORUpTime.4 = Timeticks: (12) 0:00:00.12
SNMPv2-MIB::sysORUpTime.5 = Timeticks: (12) 0:00:00.12
SNMPv2-MIB::sysORUpTime.6 = Timeticks: (12) 0:00:00.12
SNMPv2-MIB::sysORUpTime.7 = Timeticks: (18) 0:00:00.18
SNMPv2-MIB::sysORUpTime.8 = Timeticks: (18) 0:00:00.18
SNMPv2-MIB::sysORUpTime.9 = Timeticks: (18) 0:00:00.18
End of MIB
netkiller@neo:/etc/snmp$ snmpget -v 1 -c public localhost sysDescr.0
SNMPv2-MIB::sysDescr.0 = STRING: Linux neo.example.org 2.6.17-10-server #2 SMP Tue Dec 5 22:29:32 UTC 2006 i686
netkiller@neo:/etc/snmp$

7.1.3.2. snmpget

snmpget -v 1 -c public localhost sysDescr.0

snmpwalk -v 1 -c OFcx6CvN 127.0.0.1 extEntry

7.1.3.3. snmptest

			
# snmptest -v2c -c public localhost
Variable: system.sysDescr.0
Variable: system.sysContact.0
Variable: 
Received Get Response from UDP: [127.0.0.1]:161->[0.0.0.0]:48968
requestid 0x611A34EA errstat 0x0 errindex 0x0
SNMPv2-MIB::sysDescr.0 = STRING: Linux localhost.localdomain 3.10.0-123.20.1.el7.x86_64 #1 SMP Thu Jan 29 18:05:33 UTC 2015 x86_64
SNMPv2-MIB::sysContact.0 = STRING: Root <root@localhost> (configure /etc/snmp/snmp.local.conf)

7.1.4. Cisco MBI

7.1.4.1. Cisco 3750

snmpwalk -c public -v2c 172.16.1.1

system.sysDescr

$ snmpget -v2c -c public 172.16.1.1 system.sysDescr.0
SNMPv2-MIB::sysDescr.0 = STRING: Cisco IOS Software, C3750 Software (C3750-IPBASE-M), Version 12.2(35)SE5, RELEASE SOFTWARE (fc1)
Copyright (c) 1986-2007 by Cisco Systems, Inc.
Compiled Thu 19-Jul-07 19:15 by nachen

$ snmpget -v2c -c public 172.16.1.1 sysName.0
SNMPv2-MIB::sysName.0 = STRING: Switch-3750-LAN

$ snmpwalk -v2c -c public 172.16.1.1 interfaces.ifTable.ifEntry.ifDescr
IF-MIB::ifDescr.1 = STRING: Vlan1
IF-MIB::ifDescr.2 = STRING: Vlan2
IF-MIB::ifDescr.3 = STRING: Vlan3
IF-MIB::ifDescr.4 = STRING: Vlan4
IF-MIB::ifDescr.5 = STRING: Vlan5
IF-MIB::ifDescr.5179 = STRING: StackPort1
IF-MIB::ifDescr.5180 = STRING: StackSub-St1-1
IF-MIB::ifDescr.5181 = STRING: StackSub-St1-2
IF-MIB::ifDescr.10101 = STRING: GigabitEthernet1/0/1
IF-MIB::ifDescr.10102 = STRING: GigabitEthernet1/0/2
IF-MIB::ifDescr.10103 = STRING: GigabitEthernet1/0/3
IF-MIB::ifDescr.10104 = STRING: GigabitEthernet1/0/4
IF-MIB::ifDescr.10105 = STRING: GigabitEthernet1/0/5
IF-MIB::ifDescr.10106 = STRING: GigabitEthernet1/0/6
IF-MIB::ifDescr.10107 = STRING: GigabitEthernet1/0/7
IF-MIB::ifDescr.10108 = STRING: GigabitEthernet1/0/8
IF-MIB::ifDescr.10109 = STRING: GigabitEthernet1/0/9
IF-MIB::ifDescr.10110 = STRING: GigabitEthernet1/0/10
IF-MIB::ifDescr.10111 = STRING: GigabitEthernet1/0/11
IF-MIB::ifDescr.10112 = STRING: GigabitEthernet1/0/12
IF-MIB::ifDescr.10113 = STRING: GigabitEthernet1/0/13
IF-MIB::ifDescr.10114 = STRING: GigabitEthernet1/0/14
IF-MIB::ifDescr.10115 = STRING: GigabitEthernet1/0/15
IF-MIB::ifDescr.10116 = STRING: GigabitEthernet1/0/16
IF-MIB::ifDescr.10117 = STRING: GigabitEthernet1/0/17
IF-MIB::ifDescr.10118 = STRING: GigabitEthernet1/0/18
IF-MIB::ifDescr.10119 = STRING: GigabitEthernet1/0/19
IF-MIB::ifDescr.10120 = STRING: GigabitEthernet1/0/20
IF-MIB::ifDescr.10121 = STRING: GigabitEthernet1/0/21
IF-MIB::ifDescr.10122 = STRING: GigabitEthernet1/0/22
IF-MIB::ifDescr.10123 = STRING: GigabitEthernet1/0/23
IF-MIB::ifDescr.10124 = STRING: GigabitEthernet1/0/24
IF-MIB::ifDescr.10125 = STRING: GigabitEthernet1/0/25
IF-MIB::ifDescr.10126 = STRING: GigabitEthernet1/0/26
IF-MIB::ifDescr.10127 = STRING: GigabitEthernet1/0/27
IF-MIB::ifDescr.10128 = STRING: GigabitEthernet1/0/28
IF-MIB::ifDescr.14501 = STRING: Null0


$ snmpget -v2c -c public 172.16.1.1 interfaces.ifNumber.0
IF-MIB::ifNumber.0 = INTEGER: 37

7.1.4.2. Cisco ASA 5550

snmpget -v2c -c public 172.16.1.254 IF-MIB::ifInOctets.3 IF-MIB::ifInOctets.9 IF-MIB::ifOutOctets.3 IF-MIB::ifOutOctets.9
snmpget -v2c -c public 172.16.1.254 IF-MIB::ifOperStatus.3 IF-MIB::ifOperStatus.9

#!/bin/bash
echo -n `date +%H:%M:%S` " "
snmpget -v2c -c public 172.16.1.254 IF-MIB::ifInOctets.3 IF-MIB::ifInOctets.9 IF-MIB::ifOutOctets.3 IF-MIB::ifOutOctets.9 | awk -F ': ' '{print $2}' | tr "\n" " "
echo

$ crontab -l
# m h  dom mon dow   command
*/5 * * * * /home/mgmt/test/test.sh >> /home/mgmt/test/test.log

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第 7 章 網絡監控