In enterprise networks, dedicated servers are usually used to provide DHCP, DNS, TFTP, and FTP services. The clients are not generally on the same subnet as those servers. The clients used to broadcast messages to locate the servers and get services. Now, look at the figure below. Laptop0 is attempting to acquire an IPv4 address… Read more
A Cisco router can be configured as a DHCPv4 server. The DHCPv4 server assigns and manages IPv4 addresses from specified address pools within the router to DHCPv4 clients. The steps for configuring the DHCPv4 server on Cisco routers are the following: Excluding IPv4 Addresses The router configured as the DHCPv4 server assigns all IPv4 addresses
As discussed in the previous lesson, DHCPv4 clients and servers exchange messages to exchange IP address information. The format of all DHCPv4 messages is common and based on the BOOTP specification. The DHCP v4 uses UDP port numbers 67 and 68 with BOOTP. Post 68 is the DHCPv4 source port number, while port 67 is
Every device on the Internet, and every device on any network, needs a unique IP address. Network administrators can assign static IP addresses to routers, servers, and printers whose locations are not likely to change. The IP addresses assigned to these devices are usually not changed. The static addresses also enable administrators to manage these
IPv6 ACLs are similar to IPv4 ACLs. If you can understand IPv4 access lists, IPv6 ACLs are not difficult for you to understand and configure. IPv4 has two types of ACLs: standard and extended. Both can either be numbered or named ACLs, but IPv6 ACLs are only one type, similar to IPv4 extended-named ACLs in
As discussed earlier, we can troubleshoot the ACL error using the show commands. The wrong-order ACEs are the most common ACL errors. This article will discuss some common errors in ACL configuration ACL Error – Example 1 In the figure, host 192.168.2.2 has no HTTP or HTTPS access with 192.168.4.2. When entering the show access-lists
Inbound ACL Logic When a router receives a packet, it starts comparing the information in the packet header with the ACL. If the information in the packet header and an ACL entry match, the rest of the entries in ACLs are skipped, and the packet is permitted or denied as configured by the matching entry.
The number of extended ACLs starts from 100 to 199 and 2000 to 2699, providing 799 possible extended numbered ACLs. We can also create extended ACLs with the name. Extended ACLs are used more than standard ACLs because of greater control and facilities. Extended ACLs check packet source addresses, destination addresses, protocols, and port numbers.
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Social engineering is a non-technical way for a criminal to collect information on a target. It is an art of gaining entrée to buildings, systems, or data by exploiting human psychology instead of breaking in or using technical hacking techniques. For example, instead of finding software vulnerability, a social engineer might call an employee and
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Security backholes can affect web browsers. The web browser displays pop-up promotions collects identity information, or installs adware, viruses, or spyware. A cybercriminal can hack a browser’s executable file, a browser’s components, and plugins. Browser Plugins A browser plugin is a software that acts as an add-on to a browser and installs extra functions in the browser. Browser plugins