Network Layer Troubleshooting Flashcards
Network Troubleshooting: Mismatches MTU
incoming packet exceeds the Maximum Transmission Unit MTU for the router interface
Network Troubleshooting: Incorrect Subnet Mask
subnet mask is listed incorrectly, one host attempting to communicate with another on the same subnet
Network Troubleshooting: Incorrect Default Gateway
incorrect default gateway configuration, traffic is not forwarded off that hosts local subnet
Network Troubleshooting: Duplicate IP Address
hosts on the subnet are configured with the same IP address, causing unpredictable traffic patterns to occur
Network Troubleshooting: Incorrect DNS Configuration
if DNS configuration is incorrect, that host will be unable to browse using domain names
Network Troubleshooting: Duplicate MAC Address
duplicate MAC address, typically caused by a software configuration of MAC addresses
Network Troubleshooting: Expired IP Address
leased DHCP address has expired for a workstation
Network Troubleshooting: Exhausted DHCP Scope
may have a DHCP scope that has run out of addresses to lease, can be the result of a DHCP exhaustion type of attack
Network Troubleshooting: Rogue DHCP Server
can result in incorrect IP configurations, often the result of users bringing in their own devices, either maliciously or accidentally
Network Troubleshooting: Untrusted SSL Certificate
may have an issues with the SSL certificate that is preventing authentication
Network Troubleshooting: Incorrect Time
many network configurations rely on the correct time, might have problems in the network due to a workstation, server, or network appliance with the wrong time set
Network Troubleshooting: Blocked TCP/UDP Ports
blocked TCP/UDP ports are often the result of a misconfigured security device in the network path
Network Troubleshooting: Incorrect Host-Based Firewall Settings
host based firewalls are a security area that can cause problems
Network Troubleshooting: Incorrect ACL Settings
access control lists can have a direct effect on network traffic can could be the cause of one or many trouble tickets
Network Troubleshooting: Unresponsive Service
service that has failed in the network can cause problems
