I've been working on this for a couple of weeks now. We have a new installation of PRTG, and have yet to successfully connect to our CentOS servers via SNMP.
On the server where we're doing primary work:
[root@nessus ~]# netstat -tulnp Active Internet connections (only servers) Proto Recv-Q Send-Q Local Address Foreign Address State PID/Program name tcp 0 0 0.0.0.0:161 0.0.0.0:* LISTEN 35964/snmpd tcp 0 0 127.0.0.1:199 0.0.0.0:* LISTEN 35964/snmpd tcp6 0 0 ::1:161 :::* LISTEN 35964/snmpd udp 0 0 0.0.0.0:161 0.0.0.0:* 35964/snmpd udp6 0 0 ::1:161 :::* 35964/snmpd
[root@nessus snmp]# cat snmpd.conf agentAddress udp:161,udp6:[::1]:161,tcp:161,tcp6:[::1]:161 rocommunity public rwcommunity public rocommunity "prtg" 10.53.2.208
[root@nessus snmp]# ps -aux | grep snmp root 35964 0.0 0.3 229140 13136 ? Ss Apr30 2:56 /usr/sbin/snmpd -LS0-5d -Lf /dev/null -u root -g root -p /var/run/snmpd.pid -f
[root@nessus snmp]# nmap -sT -O localhost Starting Nmap 6.47 ( http://nmap.org ) at 2018-05-03 09:13 EDT Nmap scan report for localhost (127.0.0.1) Host is up (0.0011s latency). Other addresses for localhost (not scanned): 127.0.0.1 PORT STATE SERVICE 25/tcp open smtp 161/tcp open snmp 199/tcp open smux Device type: general purpose Running: Linux 3.X OS CPE: cpe:/o:linux:linux_kernel:3 OS details: Linux 3.7 - 3.15 Network Distance: 0 hops Linux 3.10.0-693.17.1.el7.x86_64
From the PRTG Windows server:
----------------------- New Test ----------------------- Paessler SNMP Tester 5.2.3 Computername: PRTG Interface: 10.53.2.208 5/3/2018 9:17:47 AM (45 ms) : Device: 10.53.2.211 5/3/2018 9:17:47 AM (50 ms) : SNMP V2c 5/3/2018 9:17:47 AM (53 ms) : Uptime 5/3/2018 9:17:58 AM (10106 ms) : SNMP Datatype: ASN_PRIMITIVE 5/3/2018 9:17:58 AM (10112 ms) : ------- 5/3/2018 9:17:58 AM (10114 ms) : DISMAN-EVENT-MIB::sysUpTimeInstance = No response (check: firewalls, routing, snmp settings of device, IPs, SNMP version, community, passwords etc) (SNMP error # -2003) ( 0 seconds ) 5/3/2018 9:18:08 AM (20122 ms) : SNMP Datatype: ASN_PRIMITIVE 5/3/2018 9:18:08 AM (20124 ms) : HOST-RESOURCES-MIB::hrSystemUptime.0 = No response (check: firewalls, routing, snmp settings of device, IPs, SNMP version, community, passwords etc) (SNMP error # -2003) ( 0 seconds ) 5/3/2018 9:18:08 AM (20126 ms) : Done ----------------------- New Test ----------------------- Paessler SNMP Tester 5.2.3 Computername: PRTG Interface: 10.53.2.208 5/3/2018 9:18:11 AM (7 ms) : Device: 10.53.2.211 5/3/2018 9:18:11 AM (10 ms) : SNMP V2c 5/3/2018 9:18:11 AM (14 ms) : Custom OID 1.3.6.1.2.1.1.3.0 5/3/2018 9:18:21 AM (10021 ms) : SNMP Datatype: ASN_PRIMITIVE 5/3/2018 9:18:21 AM (10024 ms) : ------- 5/3/2018 9:18:21 AM (10026 ms) : Value: No response (check: firewalls, routing, snmp settings of device, IPs, SNMP version, community, passwords etc) (SNMP error # -2003) 5/3/2018 9:18:21 AM (10029 ms) : Done ----------------------- New Test ----------------------- Paessler SNMP Tester 5.2.3 Computername: PRTG Interface: 10.53.2.208 5/3/2018 9:18:24 AM (10 ms) : Device: 10.53.2.211 5/3/2018 9:18:24 AM (14 ms) : SNMP V2c 5/3/2018 9:18:24 AM (19 ms) : Walk 1.3.6.1 5/3/2018 9:18:34 AM (10038 ms) : Error: -2003
Article Comments
Thanks for that; I won't publish the firewall configuration for security purposes. Kindly add the following line to your snmpd configuration file and reload the snmp daemon:
rocommunity prtg 10.53.2.208/32 agentAddress udp:161
That'll open up SNMP in general on the host, but only allow the PRTG server to actually query it.
Kind regards,
Stephan Linke, Tech Support Team
May, 2018 - Permalink
Since CentOS has a firewall up and running which blocks all but SSH and ICMP (iirc) by default, I gotta ask if that has been taken care of? :)
Kind regards,
Stephan Linke, Tech Support Team
May, 2018 - Permalink