Syslog is actually much tougher to talk about than most other monitoring subjects.  Why?  At its root it is incredibly simple.  Take a log entry, add a severity code, a facility code, a timestamp and host information then send it across the network to a central logging server via UDP on port 514. Besides being…

MIB MIB (Management Information Base) is part of a dictionary of what objects are available via SNMP.  In most cases, an MIB is built for a device, but sometimes (like Cisco) it is built for a hardware release, a software version, or a set of features.  MIBs change and are updated over time.  Make sure…

OID Ok, Let’s start with the OID.  OID stands for Object ID or Object Identifier.  Basically an address to reach an object. OIDs can either be represented as a numeric, a tree of numbers, or textual, a tree of names Examples: Numbers: 1.3.6.1.2.1.1.3 Names: iso.org.dod.internet.mgmt.mib.system.sysUpTime Note: When referencing OIDs going forward I will used the…

SNMP Starter SNMP is currently on v3.  v1, the original version, is the basis for SNMP and includes the main functions of SNMP including MIBs, Polling, and Trapping.  Technically there was a v2, but it is not used.  v2c is used instead of v2, and its main contributions were Informs, GetBulk and 64 bit counters. …

A slight variation on ICMP Ping is the TCP and UDP Ping. Some network nodes disable ICMP ping or ICMP all together.  In addition, some firewalls block ICMP packets.  When that is the case, TCP or UDP ping may be an option. Let’s start with UDP Ping. Instead of sending an ICMP packet, a UDP…

ICMP seems pretty simple, but what if I need more, well it is there.   How about changing the size of the packet to see how it changes round trip time, to test MTU or to see if packet fragmentation  is enabled?   Let’s change QOS (IP Precedence and/or DSCP) values to see how it…

Hello, Knock Knock, anyone there? Sometimes you just need to know if anyone is home. Call, text, knock, yell! The computer equivalent to ‘Are you there’ in the Ping. ICMP Ping to be exact. Maybe you have seen Hunt For Red October where Sean Connery very dramatically said “Give me a ping, Vasili. One ping…