2.5. SNMP Monitoring
Overview
Simple Network Management Protocol (SNMP) is a standardized protocol for management of
network devices. An SNMP compliant client can connect to a network device which supports the
SNMP protocol to query and control it.
NetDefendOS supports SNMP version 1 and version 2. Connection can be made by any SNMP
compliant clients to devices running NetDefendOS. however only query operations are permitted for
security reasons. Specifically, NetDefendOS supports the following SNMP request operations by a
client:
•
The GET REQUEST operation
•
The GET NEXT REQUEST operation
•
The GET BULK REQUEST operation (SNMP Version 2c only)
The NetDefendOS MIB
The Management Information Base (MIB) is a database, usually in the form of a file, which defines
the parameters on a network device that an SNMP client can query or change. The MIB file for a
device running NetDefendOS is distributed with the standard NetDefendOS distribution pack as a
file with the name DFLNNN-TRAP.MIB (where NNN indicates the model number of the firewall)
and this should be transferred to the hard disk of the workstation that will run the SNMP client so it
can be imported by the client software. When the client runs, the MIB file is accessed to inform the
client of the values that can be queried on a NetDefendOS device.
Defining SNMP Access
SNMP access is defined through the definition of a NetDefendOS Remote object with a Mode value
of SNMP. The Remote object requires the entry of:
•
Interface - The NetDefendOS interface on which SNMP requests will arrive.
•
Network - The IP address or network from which SNMP requests will come.
•
Community - The community string which provides password security for the accesses.
The Community String
Security for SNMP Versions 1 and 2c is handled by the Community String which is the same as a
password for SNMP access. The Community String should be difficult to guess and therefore be
constructed in the same way that any other password, using combinations of upper and lower case
letters with digits.
Enabling an IP Rule for SNMP
The advanced setting SNMP Before Rules in the RemoteAdmin section controls if the IP rule set
checks all accesses by SNMP clients. This is by default disabled and the recommendation is to
always enable this setting.
The effect of enabling this setting is to add an invisible Allow rule at the top of the IP rule set which
automatically permits accesses on port 161 from the network and on the interface specified for
2.5. SNMP Monitoring
Chapter 2. Management and Maintenance
69
Summary of Contents for NetDefend DFL-260E
Page 27: ...1 3 NetDefendOS State Engine Packet Flow Chapter 1 NetDefendOS Overview 27...
Page 79: ...2 7 3 Restore to Factory Defaults Chapter 2 Management and Maintenance 79...
Page 146: ...3 9 DNS Chapter 3 Fundamentals 146...
Page 227: ...4 7 5 Advanced Settings for Transparent Mode Chapter 4 Routing 227...
Page 241: ...5 4 IP Pools Chapter 5 DHCP Services 241...
Page 339: ...6 7 Blacklisting Hosts and Networks Chapter 6 Security Mechanisms 339...
Page 360: ...7 4 7 SAT and FwdFast Rules Chapter 7 Address Translation 360...
Page 382: ...8 3 Customizing HTML Pages Chapter 8 User Authentication 382...
Page 386: ...The TLS ALG 9 1 5 The TLS Alternative for VPN Chapter 9 VPN 386...
Page 439: ...Figure 9 3 PPTP Client Usage 9 5 4 PPTP L2TP Clients Chapter 9 VPN 439...
Page 450: ...9 7 6 Specific Symptoms Chapter 9 VPN 450...
Page 488: ...10 4 6 Setting Up SLB_SAT Rules Chapter 10 Traffic Management 488...
Page 503: ...11 6 HA Advanced Settings Chapter 11 High Availability 503...
Page 510: ...12 3 5 Limitations Chapter 12 ZoneDefense 510...
Page 533: ...13 9 Miscellaneous Settings Chapter 13 Advanced Settings 533...
