- root 계정으로 접속

#yum -y install net-snmp*

snmpd 의 설정파일은 /etc/snmp/snmpd.conf 파일인에, 

yum 으로 최초로 설치되는 snmpd.conf 파일 안에는 뭔가가 아주 많이 들어 있다. 

다 삭제하고 read only 로 public 커뮤니티 하나만 세팅해 보자.. 

# cd /etc/snmp

# mv /etc/snmp/snmpd.conf /etc/snmpd.conf.orig

# echo rocommunity public > snmpd.conf

이렇게 해서 /etc/snmp/snmpd.conf 파일을 열어 보면, 

rocommunity public

이렇게 한 줄만 들어가 있다. read only 커뮤니티 public 을 설정한다는 의미일 것이다. 

2. snmpd 재시작

# service snmpd restart

다른 방법

#/etc/init.d/snmpd start

방화벽 오픈 및 다른 곳에서 모니터링하기

snmp 는 UDP 161 포트를 사용하고,

snmp trap 은 UDP 162 포트를 사용한다. 

3. iptable 설정(리눅스 방화벽)

#cd /etc/sysconfig

#vi iptables

-A INPUT -P udp --dport 161 -j ACCEPT

#service iptables restart

#netstat -nulp

4. nmap 설치 미 확인

#yum -y install nmap

#nmap -sU localhost

5. localhost 의 정보를 읽어 보자

#snmpwalk

USAGE: snmpwalk [OPTIONS] AGENT [OID]

Version:  5.3.2.2

  Web:      http://www.net-snmp.org/

  Email:    net-snmp-coders@lists.sourceforge.net

OPTIONS:

  -h, --help            display this help message

  -H                    display configuration file directives understood

  -v 1|2c|3             specifies SNMP version to use

  -V, --version         display package version number

SNMP Version 1 or 2c specific

  -c COMMUNITY          set the community string

SNMP Version 3 specific

  -a PROTOCOL           set authentication protocol (MD5|SHA)

  -A PASSPHRASE         set authentication protocol pass phrase

  -e ENGINE-ID          set security engine ID (e.g. 800000020109840301)

  -E ENGINE-ID          set context engine ID (e.g. 800000020109840301)

  -l LEVEL              set security level (noAuthNoPriv|authNoPriv|authPriv)

  -n CONTEXT            set context name (e.g. bridge1)

  -u USER-NAME          set security name (e.g. bert)

  -x PROTOCOL           set privacy protocol (DES|AES)

  -X PASSPHRASE         set privacy protocol pass phrase

  -Z BOOTS,TIME         set destination engine boots/time

General communication options

  -r RETRIES            set the number of retries

  -t TIMEOUT            set the request timeout (in seconds)

Debugging

  -d                    dump input/output packets in hexadecimal

  -D[TOKEN[,...]]       turn on debugging output for the specified TOKENs

                           (ALL gives extremely verbose debugging output)

General options

  -m MIB[:...]          load given list of MIBs (ALL loads everything)

  -M DIR[:...]          look in given list of directories for MIBs

  -P MIBOPTS            Toggle various defaults controlling MIB parsing:

                          u:  allow the use of underlines in MIB symbols

                          c:  disallow the use of "--" to terminate comments

                          d:  save the DESCRIPTIONs of the MIB objects

                          e:  disable errors when MIB symbols conflict

                          w:  enable warnings when MIB symbols conflict

                          W:  enable detailed warnings when MIB symbols conflict

                          R:  replace MIB symbols from latest module

  -O OUTOPTS            Toggle various defaults controlling output display:

                          0:  print leading 0 for single-digit hex characters

                          a:  print all strings in ascii format

                          b:  do not break OID indexes down

                          e:  print enums numerically

                          E:  escape quotes in string indices

                          f:  print full OIDs on output

                          n:  print OIDs numerically

                          q:  quick print for easier parsing

                          Q:  quick print with equal-signs

                          s:  print only last symbolic element of OID

                          S:  print MIB module-id plus last element

                          t:  print timeticks unparsed as numeric integers

                          T:  print human-readable text along with hex strings

                          u:  print OIDs using UCD-style prefix suppression

                          U:  don't print units

                          v:  print values only (not OID = value)

                          x:  print all strings in hex format

                          X:  extended index format

  -I INOPTS             Toggle various defaults controlling input parsing:

                          b:  do best/regex matching to find a MIB node

                          h:  don't apply DISPLAY-HINTs

                          r:  do not check values for range/type legality

                          R:  do random access to OID labels

                          u:  top-level OIDs must have '.' prefix (UCD-style)

                          s SUFFIX:  Append all textual OIDs with SUFFIX before parsing

                          S PREFIX:  Prepend all textual OIDs with PREFIX before parsing

  -L LOGOPTS            Toggle various defaults controlling logging:

                          e:           log to standard error

                          o:           log to standard output

                          n:           don't log at all

                          f file:      log to the specified file

                          s facility:  log to syslog (via the specified facility)

                          (variants)

                          [EON] pri:   log to standard error, output or /dev/null for level 'pri' and above

                          [EON] p1-p2: log to standard error, output or /dev/null for levels 'p1' to 'p2'

                          [FS] pri token:    log to file/syslog for level 'pri' and above

                          [FS] p1-p2 token:  log to file/syslog for levels 'p1' to 'p2'

  -C APPOPTS            Set various application specific behaviours:

                          p:  print the number of variables found

                          i:  include given OID in the search range

                          I:  don't include the given OID, even if no results are returned

                          c:  do not check returned OIDs are increasing

                          t:  Display wall-clock time to complete the request

6. localhost 의 snmp 정보 모으기

#snmpwalk -v 2c -c public localhost

7. 원격지 시스템의 snmp 정보 모으기

: 원격지 시스템(넥스지 UTM을 대상으로 함 community 는 aaa로 설정 하였다

#snmpwalk -v 2c -c aaa 호스트IP

#snmpwalk -v2c -c aaa 호스트IP

SNMPv2-MIB::sysDescr.0 = STRING: Linux ns.aaa.or.kr 2.6.6-8hl #1 Tue Oct 12 00:22:29 KST 2004 i686

SNMPv2-MIB::sysObjectID.0 = OID: NET-SNMP-MIB::netSnmpAgentOIDs.10

SNMPv2-MIB::sysUpTime.0 = Timeticks: (54657) 0:09:06.57

SNMPv2-MIB::sysContact.0 = STRING: Root <root@localhost> (configure /etc/snmp/snmp.local.conf)

#snmpwalk -v2c -c read-aaa -O f 호스트IP

.iso.org.dod.internet.mgmt.mib-2.system.sysDescr.0 = STRING: Linux ns.aaa.or.kr 2.6.6-8hl #1 Tue Oct 12 00:22:29 KST 2004 i686

.iso.org.dod.internet.mgmt.mib-2.system.sysObjectID.0 = OID: .iso.org.dod.internet.private.enterprises.netSnmp.netSnmpEnumerations.netSnmpAgentOIDs.10

.iso.org.dod.internet.mgmt.mib-2.system.sysUpTime.0 = Timeticks: (47124) 0:07:51.24

.iso.org.dod.internet.mgmt.mib-2.system.sysContact.0 = STRING: Root <root@localhost> (configure /etc/snmp/snmp.local.conf)

#snmpwalk -v2c -c aaa -O fn 호스트IP

 .1.3.6.1.2.1.1.1.0 = STRING: Linux ns.aaa.or.kr 2.6.6-8hl #1 Tue Oct 12 00:22:29 KST 2004 i686

 .1.3.6.1.2.1.1.2.0 = OID: .1.3.6.1.4.1.8072.3.2.10

 .1.3.6.1.2.1.1.3.0 = Timeticks: (76934) 0:12:49.34

 .1.3.6.1.2.1.1.4.0 = STRING: Root <root@localhost> (configure /etc/snmp/snmp.local.conf)