Embed Size (px)
Citation preview
Overview
• Introduction• DNS• Ping• WMI• Conclusion
Introduction
• Network protocols are not just used to move data from one point to another.
• Some protocols have specific purposes that help keep Internet traffic flowing and make using the network easier.
• These utility protocols may not be required for every network application;
• however, because these are niche technologies, many developers may not know how to implement such features
DNS
• DNS operates on UDP port 53 and is described in RFC 1010, RFC 1304, RFC 1035, and RFC 1183
• the most common use for DNS is to convert domain names into IP addresses because people find it difficult to remember strings of numbers more than nine digits long
• DNS was developed to provide a system that converts easily recognizable domain names into IP addresses
• You can use DNS.GetHostByName to convert a domain name () to an IP address ()
• The reverse of this action, converting an IP address to a domain name, can be achieved using IPHostEntry DNS.GetHostByAddress.
Implementing DNS MX
• Open a new project in Visual Studio .NET and draw three textboxes named– tbDNSServer– tbDomain– tbStatus
• the latter having multiline set to true• Button named btnFind• For the coding see your self at the ebook
Ping
• Ping or ICMP a protocol used to report broken network connections or other router-level problems that end hosts might need to know
• Many developers are familiar with the ping utility, which can be used to determine if a computer is switched on or not and how much delay there is over the connection to it.
• This protocol can be implemented in .NET to provide applications with the ability to check quickly if a computer to which it needs to connect is turned on.
• It is possible to send a ping by constructing it with a raw socket; an example of this can be seen at www.eggheadcafe.com/articles/20020209.asp.
• A simpler implementation is to use the ICMP DLL, which is standard to all Windows platforms.
• For Coding, see your self at EBook
WHOIS
• WHOIS (“who is”) is a protocol that can be used to query the registrant of a domain name.
• It runs on TCP port 43 and is described definitively in RFC 954.
• This information includes the name and company of the person who bought the domain name, along with details of the DNS servers for that domain and the operator(s) of those servers.
• Performing a WHOIS query with .NET is easy. All that is required is to open a TCP connection on port 43, send the domain name followed by the new line character, and read back the response until the connection closes.
• For coding, see for yourself at the EBook
Telnet
• Telnet could be used as a back end to a remote configuration console for a UNIX product, but beyond that, it would rarely be used programmatically
• Telnet often used to debug servers and investigate new TCPbased protocols because all telnet clients provide the option to connect on ports other than 23.
Other members of the TCP/IP suite
• ARP Address resolution protocol• RIP Routing information protocol• OSPF Open shortest path first• BGP/EGP Border gateway protocol (BGP)
supersedes exterior gateway protocol• SNMP Simple network management
protocol• PPP Point-to-point protocol
WMI
• WMI, or Windows Management Instrumentation, is used within a Windows intranet to provide a facility to perform simple administrative tasks remotely
• One of the main uses of WMI is to extract technical information about remote Windows systems
• WMI is structured somewhat like a database
Reading WMI data
• WMI data may resemble a database conceptually, but the System.Management namespace, which encapsulates WMI, is dissimilar to the data access namespaces.
• WMI uses a ManagementScope that is passed the location of the remote computer in the format \\<host name>\root\namespace and a ConnectionOptions object that contains the logon credentials (username and password).
Conclusion
• This chapter has dealt with a set of network protocols that are not suited to moving bulk data among machines, but are particularly valuable in adding features and improving the performance of distributed applications
• The chapter concluded with a look at a surprisingly versatile Microsoft technology, WMI, which can pull virtually every conceivable piece of technical information from a remote computer over.
• WMI is an absolutely essential technology for internal IT support.
The End …
• Question
