Learn about network experience--the next

Repeated experiments.

For administrators, there may be a lot of experimentation to be done:

(1) When learning new knowledge. For a new point of knowledge, we want to set up an experimental environment, to verify the content of the learning, for the "branch" of the content, each branch may have to verify, at least to verify that the knowledge of our useful, these need to experiment, and time, patience.

(2) Reproduce the fault: in our analysis of failure, analysis of the problem, we need to reproduce the failure, this time also need to repeat the experiment.

(3) Planning and design: in our planning and design, we need to test the content of the design, we need to prepare the experimental environment, through experiments to verify. If the production environment is licensed, it is designed in a production environment. For example, when we configure a virtualized datacenter, we start by not running production data, but instead give the administrator some time to familiarize administrators, such as configuring storage, adding virtual machines, deleting virtual machines, deploying virtual machines from templates, and so on. After the administrator is familiar with these operations, then the production data. These are all part of the experiment.

(4) Migration upgrade: Before the migration upgrade, we had better simulate the production environment, first in the experimental environment, and then in the production environment for the actual operation. For example, after I upgrade my network from Windows Server 2003 to Windows Server 2003 R2, upgrade to Windows Server 2008 again, and upgrade to Windows Server R2 until now the latest Windows Server R2, I verify it in the virtual machine. While these are only related to server operating system upgrades, there are also applications that are integrated with these systems, such as DHCP servers, certificate servers, and so on, which need to be upgraded. It can be said that the upgrade is more complex than the new installation, and there may be many problems encountered. In addition, the lab environment is built when the system migrates, such as changing the storage location for Exchange Server 2010, upgrading from an Exchange low version to a higher version, and so on.

Figure 4 is my VMware Workstation main console interface, which is the template virtual machine I configured on the left, as well as the virtual machines used or used in the experiment.

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Figure 4 VMware Workstation virtual machine software

Draw a topology diagram

Sometimes, "figure" provides a bridge for us to communicate with our users. A simple diagram can show our ideas at a glance for the user. Similarly, in our learning process, often do map, record the knowledge points of learning, or master the content of learning, more than the text effect. Of course, there must be some text in the picture.

Especially for the network, involves the IP address, the equipment is many, the connection way may also very complex, if has a very good topology diagram, can quickly understand the network structure, the connection way, also can quickly grasp the network. Figure 5~ Figure 7 is a unit of network equipment topology diagram, Server virtualization topology diagram and unit network topology diagram.

Figure 5 is a topology diagram of the switch, and you can see the connections of each switch. It can also be labeled in the diagram, which is the properties of the port connected through that port.

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Figure 5 Network topology diagram

Figure 6 is a unit of Vsphere data center virtualization, indicating the server's network connectivity, Virtual Switch network allocation, the server's management address and other content. With this diagram, you can manage each server and each virtual machine.

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Figure 6 Server Virtualization

Figure 7 is a more detailed topology, indicating the current network of major devices (including firewalls, traffic control, core switches, servers and various virtual machines in the server), through this diagram, any network equipment problems, can determine the location of the problem, and locate the relevant equipment for analysis, judgment.

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Figure 7 Network device and server topology diagram

When the topological map is very thin, if the user's network is out of the question, we can analyze and judge according to the topological map, diagnose the problem, help the user to solve the problem. Finally, if the user's network topology or IP address changes, but also to update the topology map in a timely manner. The updated topology diagram (or configuration file) is also sent to the user in a timely manner.

To apply

When we go to school, the knowledge we learn is very wide.

When we work, the knowledge used is very close to the point.

Because when school, is according to the hobby, the interest to study, all related books, can borrow to look at the study. And after work, our study may have a very strong purpose: I learned this can be used, can solve any problem. If the knowledge is used in practical, solve the problems encountered in the actual work, more conducive to the mastery of knowledge.

For example, we have learned the subnet mask, IP address division, according to our current computer's IP address, subnet mask, calculate the current network, the maximum number of computers can be accommodated. Or, try to plan and assign IP addresses for your current network, and you can analyze whether there are problems with the planning of IP addresses in your current network.

For example, we learned the DHCP service and understood the IP address acquisition, release, DHCP address pool, scope, DNS and other parameters, you can solve similar problems. An Administrative service center, in order to facilitate the public, in the Executive Service center of the business Hall to provide free WiFi service, after a period of time, found that every morning to work in the majority of the public can use the lobby to provide WiFi connection to access the Internet, but in the afternoon, can not access. When the business is busy, you cannot access the network until after 11 o'clock in the morning. At first glance, this is a matter of time, but in fact, the reason for this problem is simple: The DHCP address is not enough. This case is shown in topology 8.

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Figure 8 Wireless network topology diagram

In this case, the three-layer switch divides the network segments into a C-class network segment for the lobby using WiFi users, which is configured in the Internet behavior and firewall. Lobby use WiFi users can only access the Internet and cannot access the internal network. In the initial design, in the hall at the same time do business people will not have 200 internet, so planning C-class address should be enough, but the designer forgot, DHCP lease time. In this case, using the Huawei three layer switch to assign IP addresses to wifi users, the default IP address lease time is 1 days (i.e. 24 hours) by default when the Huawei switch configures DHCP. After the user obtains an address from the switch, the address can be redistributed on the 2nd day. This led to the beginning of the day to get the address of 253 people can use, the No. 254 person again connected no doubt the router, because there is no address in the DHCP address pool, and can not get the address, can not access the network.

Understand the cause of the problem, and then the solution is very simple, into the switch configuration, the switch DHCP lease time to a reasonable time, for example, to 30 minutes, the main configuration is as follows:

DHCP server Ip-pool vlan68

Network 192.168.68.0 Mask 255.255.255.0

Gateway-list 192.168.68.254

Dns-list 202.99.160.68

Expired Day 0 hour 0 minute 30

Multi-Design Solutions

The above introduction to "Application of knowledge", in addition to solve problems, troubleshooting, there is another aspect, is nearly possible multi-design applications. Every point of knowledge we learn can resonate with us to solve problems in real life or work. We can behave in a programmatic way, and from a single point of view, the scenario may be smaller, but the cumulative design is much more, and can provide a good basis for us to design more complex and larger applications. In addition, the scheme can also be used for reference with the general, we design for a unit, the change can then use in B units.

At the beginning, may not know how to do, how to design the plan, at this time can look at others design plans, and modeled these plans, the existing solutions to improve the design of their own units to adapt to the application program. In my blog (http://wangchunhai.blog.51cto.com), there are a number of applications that address practical uses of "small" design and problem solving, such as "Considerations for computer join to the domain (http:// wangchunhai.blog.51cto.com/225186/1391814) "," use a smart card to provide BitLocker Drive Encryption (http://wangchunhai.blog.51cto.com/225186/ 1250833) "," Configuring the image for SQL Server 2012 considerations and the use of SSD drives as a database storage disk (http://wangchunhai.blog.51cto.com/225186/1176653) "," Add ' Internet Printing ' feature (http://wangchunhai.blog.51cto.com/225186/1156589) to Windows 7, "using intelligent DNS and multi-line routing to troubleshoot education network server costs (http:/ /wangchunhai.blog.51cto.com/225186/1143846) "," in Remote Desktop Services Configuration Rd Thunder Direct Access Intranet (http://wangchunhai.blog.51cto.com/225186/ 1139388) "and so on.

Other people's Stone, can attack Jade. See more, learn more, their own design more, slowly can be their own independent design and application of the enterprise, will eventually become an enviable "master".

How to ask questions

Although we have become the "master" in the eyes of others, but it is not omnipotent. What if we do not understand the problem, need to ask? I give you some of my experience. First need a detailed network diagram, draw clear network equipment (switches, routers, firewalls), computer and server equipment, connection mode, IP address, from where to where the problem, will you need to solve the problem of writing a document, map topology, on the topology map on the main device's IP address, Then simply describe the phenomenon of failure, what problems encountered, you are how to judge the analysis, you get the results of what, nearly possible to clear the problem once. This allows the person receiving the question to quickly understand the problem and help you solve it in the shortest possible time. If the expression is not clear, you can use "Remote Assistance" way, let others help you analyze, view.

Very taboo way of questioning: in it? Can I ask you a question? My network is not through, how to solve? These are not possible, want to help your people do not know anything is also anxious wasted each other's time.

Engaged in network work for many years a little experience with everyone to share, hope to be helpful to everyone.

This article from "Wang Chunhai blog" blog, declined reprint!

Learn about network experience--the next