Skill 4.2: Configure secure access to virtual networks Network security groups (NSGs) control which network flows are permitted into and out of your virtual networks and virtual machines. Each NSG contains lists of inbound and outbound rules, which give you fine-grained control over exactly which network flows are allowed or denied. Combine this with the…
DNS Message Format
DNS Message Format (25.1.3) The DNS server stores different types of resource records that are used to resolve names. These records contain the name, address, and type of record. Some of these record types are as follows: • A – An end device IPv4 address • NS – An authoritative name server • AAAA –…
Troubleshoot network connectivity
Troubleshoot network connectivity Azure provides several built-in tools to troubleshoot network connectivity, with most of them available through Network Watcher. This section focuses on two of the tools within Network Watcher that can help you troubleshoot network connectivity. Connection Troubleshoot Connection Troubleshoot is a Network Watcher feature designed to test the connectivity between an Azure…
IP Addressing Services – 100-150 Exam Guide
Objectives Upon completion of this chapter, you will be able to answer the following questions: • How does DNS operate? • How does DHCP operate? Key Terms This chapter uses the following key terms. You can find the definitions in the Glossary. Domain Name System (DNS) Dynamic Host Configuration Protocol (DHCP) fully-qualified domain names (FQDNs)…
Forced tunneling – MS AZ-104 Exam Guide
Forced tunneling A special case is when routes are configured with the destination IP prefix 0.0.0.0/0. Given the precedence rules described earlier, this route controls traffic destined for any IP address not covered by any other rules. By default, Azure implements a system route directing all traffic matching 0.0.0.0/0 (and not matching any other route)…
Address Resolution Summary
Address Resolution Summary (24.2) The following is a summary of each topic in the chapter and some questions for your reflection. What Did I Learn in this Module? (24.2.1) To send a packet to another host on the same local IPv4 network, a host must know the IPv4 address and the MAC address of the…
Removing Entries from an ARP Table
Removing Entries from an ARP Table (24.1.6) For each device, an ARP cache timer removes ARP entries that have not been used for a specified period of time. The times differ depending on the operating system of the device. For example, newer Windows operating systems store ARP table entries between 15 and 45 seconds, as…
IP forwarding – MS AZ-104 Exam Guide
IP forwardingUser-defined routes (UDR) change the default system routes that Azure creates for you in an Azure VNet. In the virtual appliance scenario, UDRs forward traffic to a virtual appliance such as a firewall, which is running as an Azure virtual machine.By default, a virtual machine in Azure will not accept a network packet addressed…
Video – ARP Operation – ARP Reply
Video – ARP Operation – ARP Reply (24.1.4) Only the device with the target IPv4 address associated with the ARP request will respond with an ARP reply. The ARP reply is encapsulated in an Ethernet frame using the following header information: • Destination MAC address — This is the MAC address of the sender of…
ARP Functions – 100-150 Exam Guide
ARP Functions (24.1.2) When a packet is sent to the data link layer to be encapsulated into an Ethernet frame, the device refers to a table in its memory to find the MAC address that is mapped to the IPv4 address. This table is stored temporarily in RAM memory and called the ARP table or…