Network TroubleshootingNMS

1
Network Troubleshooting/NMS
2
Client Networking

• MAC
• IP Settings
• IP
• Netmask/Subnet Mask
• Gateway
• DNS
• Tools
• ipconfig
• Winipcfg
• nslookup
• telnet
• ping
• tracert

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Client Networking - MAC

• MAC Address
• Media Access Control
• 48 bits
• Represented as 12 hexadecimal characters or 6
  delimited octets (in hex)

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Client Networking IP Settings

• IP Address
• 32 bits
• Represented as 4 octets separated by periods
• Subnet Mask
• Bit mask to determine network, broadcast and
  local addresses

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Client Networking IP Settings

• Gateway Default Route
• If the address is not within the local network it
  is sent to the default route address
• UI network standards use the first usable network
  IP address as the gateway
• DNS Domain Name System
• Resolves human readable name to IP address

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Client Networking - Tools

• ipconfig

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Client Networking - Tools

• ipconfig /all more

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Client Networking - Tools

• winipcfg

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Client Networking - Tools

• winipcfg More Info

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Client Networking - Tools

• Nslookup
• Windows NT/2000/XP
• Displays DNS information
• Includes CNAME/Aliases
• Can be used for alternate DNS attribute lookup
• No arguments enters interactive mode

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Client Networking - Tools

• Nslookup

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Client Networking - Tools

• Nslookup

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Client Networking - Tools

• telnet
• Useful for connecting to tcp service ports
• telnet lthostnamegt ltport or service namegt
• Uses local services file to resolve port
• Some common service names and ports
• smtp 25
• pop 110
• imap 143
• telnet smtp.uidaho.edu smtp

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Client Networking - Tools

• ping
• Packet INternet Groper
• Sends ICMP echo requests to remote host
• Not always reliable, use telnet if possible
• ping lthostname or ip addressgt
• ping t lthostgt (continuous ping)

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Client Networking - Tools

• ping

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Client Networking - Tools

• ping
• Using ping for troubleshooting
• ping 127.0.0.1
• Tests local tcp/ip stack
• ping ltlocal ipgt
• Tests hardware/network device driver
• ping ltgatewaygt
• Tests local subnet communication
• ping ltremote ipgt
• Tests complete trip to destination
• Warning using a host name relies on name
  resolution

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Client Networking - Tools

• tracert (traceroute)
• Uses ICMP
• Displays hops/routes in path to host

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NMS

• Navigation
• Physical Layer
• Network Layer
• Looking Up Information
• Wallplate
• Network
• MAC
• Entering Information
• Troubleshooting
• MAC Record on Proper Network
• View Port Counters

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NMS - Navigation

• Physical Layer (physical assets)
• Buildings, closets, hubs, hub ports, wallplates
• Network Layer (logical assets)
• Networks, MAC records, Domains

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NMS - Navigation

• Wallplate
• Format ltbuildinggtltclosetgtltroomgtltwallplategtltportgt
• Example
• 001a132-01b
• Building 001
• Closet A
• Room 132 (pad to 4 characters with hyphen)
• Wallplate 01
• Port B (most ports are A top, B middle, C
  bottom)
• UI standards are to populate A with phone, B with
  data and leave C available. Phones or data can
  be used in ANY port

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NMS - Navigation

• Wallplate
• Searching for a wallplate will return its
  hub/switch port or phone association.
• No reference to wiring code means there is
  either no association/patch or the wallplate does
  not exist. Leave off the port to see if the
  wallplate is valid (ex. 001a132-01)
• A hub/switch port is the location on the
  hub/switch device where the wallplate terminates.
• Hub Port Format ltbuildinggtltclosetgtltstackgtltstack
  unitgtltportgt
• Example 001a1106
• Building 001
• Closet A
• Stack 1
• Stack Unit 1 (switches cannot be stacked so
  they are always 1)
• Port 06

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NMS - Navigation

• VLAN
• Virtual LAN
• The ability to connect multiple devices together
  as though they were on the same physical network,
  regardless of the true underlying network
• All NMS networks are part of defined VLANs
• NMS currently lacks the ability to lookup VLANs
  and the networks contained within a VLAN
• The gateway for a network will show the VLAN the
  network is a member of

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NMS - Navigation

• Network
• 129.101 is a B class IP network
• UI subnets 129.101 into 4 subnet classes
• A 1024 addresses (255.255.240.0)
• B 256 addresses (255.255.255.0)
• C 64 addresses (255.255.255.192)
• D 16 addresses (255.255.255.240)
• Currently each MAC record resides in a single
  network
• Each hub/switch port is on a single network
• Networks can have multiple alternate/secondary
  networks part of the same VLAN

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NMS - Navigation

• Network
• Determine the network by clicking Up to Hub
  when viewing a hub/switch port. The default
  network for the device is displayed.
• Warning switches can be in multiple networks.
  The default network is not necessarily the same
  as the port. View port counters will display the
  vlan for the switch port.

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NMS - Navigation

• MAC
• MAC records can be found through mac address, ip
  or dns name.
• Records are associated with a single network.
• Network history is determined by an active
  process running every few minutes scanning
  network devices.
• Warning network history may not be correct due
  to a number of issues (if the remote system was
  on at the time of polling, if the hub/switch is
  capable of being polled). Use View Port
  Counters to view real-time usage.

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NMS - Navigation

• MAC
• Creating MAC Records
• Determine proper network based on wallplate
• Select Create a new MAC record on main network
  layer menu or select Create a MAC record on this
  network after select Up to Hub.
• MAC record information is propagated to all
  services in 10 minutes.

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NMS - Navigation

• Troubleshooting
• MAC record is not on the proper network
• View wallplate and hub default network to
  determine proper network (or secondary network)
• View Port Counters
• Link signal can be used to determine proper
  wallpate to port association
• Current known MAC address
• Number of errors

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NMS - Navigation

• Troubleshooting
• NRG Graphs under Port number
• When viewing a port/wallplate id, the Port
  number is linked to NRG graph data for network
  activity on the port