FortiGate
FortiGate Next Generation Firewall utilizes purpose-built security processors and threat intelligence security services from FortiGuard labs to deliver top-rated protection and high performance, including encrypted traffic.
aneshcheret
Staff
Staff
Article Id 197140
Description

This article describes how to solve SNMPwalk errors as the one below:

 

Error: OID not increasing

 

This error is caused by interface snmp-index duplicates. This occurs when SNMP indexes in the configuration are not auto-corrected (duplicate indexes). This can only occur when the configuration file was manually modified with a text editor, which is not a supported method for modifying the configuration.

Scope 

FortiOS.

Solution

Using SNMP walk tools sometimes can show the error:

 

 
snmpwalk -v2c -cC -c infoAMT 10.7.19.132
.
.
.
.
.
iso.3.6.1.2.1.2.2.1.1.1 = INTEGER: 1
iso.3.6.1.2.1.2.2.1.1.4 = INTEGER: 4
iso.3.6.1.2.1.2.2.1.1.7 = INTEGER: 7
iso.3.6.1.2.1.2.2.1.1.8 = INTEGER: 8 ------------- Value X
iso.3.6.1.2.1.2.2.1.1.8 = INTEGER: 8 ------------- Value X
 
Error: OID not increasing: iso.3.6.1.2.1.2.2.1.1.8
>= iso.3.6.1.2.1.2.2.1.1.8
 
This error means the SNMP index is not increasing. The last value represents the SNMP-Index Interface. These loops occur when SNMP indexes in the configuration are not auto-corrected (duplicate indexes). 
 
Example:
 
config system interface
    edit "port1"
        set snmp-index 8 ----> Index.
    next 
    edit "port2"
        set snmp-index 8----> Index.
end
 
Port1 and Port2 have the same index.
Solution:
Edit the interfaces and change the SNMP-Index value. In this case, the administrator needs to edit these interfaces and configure different Indexes:
 
config system interface
    edit port1
        set snmp-index 2 ----> New Index value 2.
    next
    edit port2 
        set snmp-index 3 ----> New Index value 3.
end
 

Use the sniffer below to verify values in packet capture: 

 

diagnose sniffer packet any " host x.x.x.x and port 161 " 6 0 l   <----- x.x.x.x is the snmp server IP address.

 

Type Ctrl+C to stop the sniffer.

 

Example: From the screenshot below, FortiGate reports the status to the SNMP server 10.161.85110 of all interface statuses. 

 

image.png

 

Related articles:

Technical Tip: How to import 'diagnose sniffer packet' data to WireShark 

Troubleshooting Tip: Packet Capture on FortiOS GUI