This chapter explains the operations of the different types of firewall technologies and the role they play in network access control and security architectures. It also describes guidelines for firewall rule set creation. The chapter then describes the function and building blocks of Network Address Translation.
Định tuyến và lọc lưu lượng mạng Phần 3: Network Address Translation
Network Address Translation Do các địa chỉ IPv4 là một tài nguyên có hạn và đã đến lúc đáng báo động, do đó hầu hết các ISP đều chỉ cung cấp một địa chỉ cho một khách hàng nào đó. Trong phần lớn các trường hợp, địa chỉ này được gán động, vì vậy mỗi
lần máy khách kết nối đến IPS, một địa chỉ khác sẽ được cung cấp.
A short term solution to the problem of the depletion of IP addresses
Long term solution is IP v6 (or whatever is finally agreed on)
CIDR (Classless InterDomain Routing ) is a possible short term solution
NAT is another
NAT is a way to conserve IP addresses
Hide a number of hosts behind a single IP address
192.168.0.0-192.168.255.255 for local networks
Parts 1 to 5, for each network topology: Determine the number of subnets; Design an appropriate addressing scheme; Assign addresses and subnet mask pairs to device interfaces; Examine the use of the available network address space and future growth potential.
Objectives: Design a Network Subnetting Scheme, Configure the Devices, Test and Troubleshoot the Network. Background/Scenario: In this lab, starting from a single network address and network mask, you will subnet the network into multiple subnets.
Objectives: Access the Windows Calculator, Convert between Numbering Systems, Convert Host IPv4 Addresses and Subnet Masks into Binary, Determine the Number of Hosts in a Network Using Powers of 2, Convert MAC Addresses and IPv6 Addresses to Binary.
This chapter has outlined: How NAT is used to help alleviate the depletion of the IPv4 address space; NAT conserves public address space and saves considerable administrative overhead in managing adds, moves, and changes; NAT for IPv4; The configuration, verification, and analysis of static NAT, dynamic NAT, and NAT with overloading;... Inviting you to refer lecture for more information.
Networks, particularly large networks, are often divided into smaller subnetworks, or subnets. Subnets can improve network performance and control. A subnet address extends the network portion, and is created by borrowing bits from the original host portion and designating them as the subnet field,...
DNS, DHCP, and IP Address Management
Policies Based on IP Addresses
Intelligent Network Users
User Provisioning Scalable Reliable DNS/DHCP Service
Automated Network Addressing
User-Based Policy Networking
Managing Names and Addresses
Edit by Hand
Migrating to Directories
Etc. Firewall DNS DHCP
PC Inventory PC Inventory
DHCP DHCP Policy Policy
Single Source of Data
Multiple Sources of Data...
As of November 8, 2010, Manually entered IP addresses are no longer supported on campus if the device is capable of using DHCP. This is true for normal dynamically assigned IP's and Static IP's. All NEW devices added to the network must be set to receive their network address via DHCP (Dynamic Host Configuration Protocol). This is the default setting for campus PC and Mac workstations and most printers. No user action is anticipated. There is no change or downtime expected for the vast majority of campus workstations or devices. We have made great efforts to put exceptions in place...
By looking at the addressing structures, you can see that even with a Class C address, there are a large number of hosts per network. Such a structure is an inefficient use of addresses if each end of a routed link requires a different network number. It is unlikely that the smaller office LANs would have that many devices. You can resolve this problem by using a technique known as subnet addressing.
• Network address là địa chỉ xác định một mạng riêng biệt, là cơ sở để phân biệt với các mạng khác. • 2 host khác địa chỉ mạng phải được nối với nhau thông qua một thiết bị định tuyến (Router) • Địa chỉ mạng kết thúc với tất cả các bit host là bit 0
[ Team LiB ] Recipe 1.6 Using an IP Address to Connect to SQL Server Problem You want to connect to a SQL Server using its IP address instead of its server name. Solution Use the Network Address and Network Library attributes of the connection string
IP best-effort packet-delivery service:
IP addressing and packet forwarding with datagram mode.
Multiplexing accomplished by transport protocols (TCP, UDP).
And how to build on top of the narrow waist:
Domain Name System (DNS) for resolution between name and
Dynamic host configuration protocol-DHCP for IP
Analyze a Class A network address with the number of network bits specified in order to determine the following:
• Subnet mask
• Number of subnets
• Hosts per subnet
• Information about specific subnets
NAT là 1 chức năng trên Router. NAT là cầu nối giữa IP Public và IP Private. NAT giúp các máy nội bộ có thể truy cập Internet và giúp các máy ngoài Internet có thể liên lạc với nội bộ thông qua Router.