Network Administrator
Here are some things you may need to know to be a good network administrator.

Definitions

Significance of events:

  • Informational: This refers to an event that does not require any action and does not represent an exception.
    • Configuration changes
    • critical file edits
      • /boot
      • /etc/groups
      • /etc/passwd
      • hosts file
      • httpd.conf
      • resolv.conf
      • /sbin/*
      • tnsnames.ora
    • Database access
    • failed login attempts
    • OS commands
      • ifconfig
    • Software licensing usage
  • Warning: A warning is an event that is generated when a service or device is approaching a threshold.
    • application (re)starts
    • Capacity
      • CPU utilization
      • I/O thresholds
      • Memory usage
      • Partition usage
      • Swap usage
    • Dependency availability
    • Loss of redundancy
    • server restarts
    • syslog - crit, alert, emerg, and panic events
  • Exception: An exception means that a service or device is currently operating abnormally (however that has been defined).
    • Availability, Reliability
    • Customer Experience, KPIs
    • Network or port connectivity
      • (D)DOS attacks
      • ICMP connectivity
      • Security or network intrusions
      • SNMP connectivity
    • NFS server connectivity
    • Process taking too long
    • Process returns errors
    • Response Time
    • Too many / few processes
    • VIP failures

Protocols

Problem Solving

Redundancy and failovers

  • Active – active
  • Active – Passive
  • Failover testing
  • Networking
  • Layer 2
  • Layer 3
  • Tcpdump

Security

  • Close open ports
  • Disable unneeded services
  • Monitor unauthorized access attempts
  • ACLs
  • Firewalls

Security

  • crit and above should be monitored
  • Helpful in troubleshooting

Scripting

  • Must be able to read other people\’s code
  • Must test it before implementing in production
  • Better learn how to write in at least one of the following:

Documentation

  • 75% of all code is written after release
  • Share knowledge with team members frees your time
  • Do not revisit problems you have already solved
  • Searching accounts for 50% of your work

Lead by example

  • If you see an opportunity, fix it. Don’t wait on someone else to fix it for you.
  • It is easier to ask for forgiveness, than ask for permission.
  • Communicate 3x or more.
 
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