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#5.1.1.7 using wireshark to examine ethernet frames mac#What portion of the MAC address is the OUI? What is the Vendor ID (OUI) of the Source NIC in the ARP reply? It varies in this case, it is f0:1f:af:50:fd:c8. What is the MAC address of the source in the first frame? The ARP broadcast is used to request the MAC address of the host with the IP address contained in the ARP. #5.1.1.7 using wireshark to examine ethernet frames Pc#The PC cannot send a ping request to a host until it determines the destination MAC address, so that it can build the frame header for that ping request. Why does the PC send out a broadcast ARP prior to sending the first ping request? This reply contains the MAC address of the NIC of the default gateway. The host with the IP address of 192.168.1.1 (default gateway) will send a unicast reply to the source (PC host). What is significant about the contents of the destination address field?Īll hosts on the LAN will receive this broadcast frame. The value is computed by the sending device, encompassing frame addresses, type, and data field. FCS Not shown in capture Frame Check Sequence, used by the NIC to identify errors during transmission. The data field is between 46 – 1,500 bytes. Two common frame types are these:Ġx0806 Address Resolution Protocol (ARP) Data ARP Contains the encapsulated upper-level protocol. There are numerous upper-layer protocols supported by Ethernet II. Frame Type 0x0806 For Ethernet II frames, this field contains a hexadecimal value that is used to indicate the type of upper-layer protocol in the data field. ![]() #5.1.1.7 using wireshark to examine ethernet frames serial number#Each address is 48 bits long, or 6 octets, expressed as 12 hexadecimal digits, 0-9,A-F.Ī common format is 12:34:56:78:9A:BC.The first six hex numbers indicate the manufacturer of the network interface card (NIC), the last six hex numbers are the serial number of the NIC.The destination address may be a broadcast, which contains all ones, or a unicast. Field Value Description Preamble Not shown in capture This field contains synchronizing bits, processed by the NIC hardware. The following table takes the first frame in the Wireshark capture and displays the data in the Ethernet II header fields. Step 4: Examine the Ethernet II header contents of an ARP request. This screenshot highlights the frame details for an ARP reply. This screenshot highlights the frame details for an ARP request. The session begins with an ARP query and reply for the MAC address of the gateway router, followed by four ping requests and replies. ARP is a communication protocol that is used for determining the MAC address that is associated with the IP address. ARP stands for address resolution protocol. A filter has been applied to Wireshark to view the ARP and ICMP protocols only. The screenshots of the Wireshark capture below shows the packets generated by a ping being issued from a PC host to its default gateway. Step 3: Examine Ethernet frames in a Wireshark capture. : Saturday, Septem11:08:36 AMĭefault Gateway. : Intel(R) 82579LM Gigabit Network Connection In this example, this PC host IP address is 192.168.1.147 and the default gateway has an IP address of 192.168.1.1. Type Data FCS 8 Bytes 6 Bytes 6 Bytes 2 Bytes 46 – 1500 Bytes 4 Bytes Step 2: Examine the network configuration of the PC. ![]() Step 1: Review the Ethernet II header field descriptions and lengths. A Wireshark capture will be used to examine the contents in those fields. In Part 1, you will examine the header fields and content in an Ethernet II frame.
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