In Feburary 2016 28,
Oracle servers run both an Oracle database and listener process. One Oracle listener, which you can configure to support multiple databases, receives and manages client connection requests. If the listener receives more requests than it can handle, user requests can time out; in this case, restarting the listener will resolve the error.
Database Connection
Oracle database connection requests aren't processed unless they include authentication information such as a user name, password and the name of the Oracle service. If the authentication services aren't running or the password name is incorrect, communication efforts will fail. Similarly, if the Oracle database locks up and fails to respond to database queries, Oracle will report a failure. According to “Oracle Dba on Unix and Linux” by Michael Wessler, if the Oracle database itself crashes, the program's background processes such as PMON and SMON will terminate, and you will receive an “ORA-12637 packet receive failed” or 'TNS: packet writer failure' message.
Server & Hardware
The Tnsnames.ora file on your computer contains references to Oracle servers with which it regularly communicates. If a server name is incorrect or incomplete, Oracle can't connect to it. If the port referenced in the Tnsnames.ora file isn't open, you may see an “ORA-12637 packet receive failed” message. Router and network interface controller, or NIC, card failures also cause this problem, as can insufficient server disk input/output and system memory.
Communication
Packet communication errors can occur when a network's data traffic is so great that the time-out limit hits before your computer receives a response from the Oracle server. If the packet sizes are too large for the server to process, you can change the transport date unit, or TDU, parameters in the Tnsnames.ora file. If a network router fails and the data packets are routed to other nodes that cannot handle the load, error messages will result. You also might see errors from a malicious denial-of-service attack, or hackers turning off the Oracle listener, although the latter appears as a process failure.
In Feburary 2016 28,
Showing posts with label failure. Show all posts
Showing posts with label failure. Show all posts
Sunday, 28 February 2016
Microsoft Exchange Server TutorialIn Feburary 2016 28,
In Feburary 2016 28,
Microsoft Exchange Server is part of the Microsoft Windows Server line, and is intended to deliver a platform for messaging and collaboration. The primary features of Exchange Server include email, calendaring, contacts and tasks. Exchange Server also provides a platform for mobile and web-based users who need to be able to access their data remotely, as well as support for data storage.
Enhanced Features
Microsoft Exchange Server was first launched in 1996; more recent versions, such as Exchange Server 2007 and recently released Exchange Server 2010, include many enhancements from its original version. Some of these are:
Security: Exchange Server now includes anti-spam and anti-virus filtering, as well as encryption technology. This protects users' data from outside intrusion and corruption.
Data Protection: Exchange Servers can be used in a cluster environment, which replicates the data across several servers and guarantees its availability. In this way, there can be no single point of failure; if one server goes down, the other servers will pick up the slack and continue to provide data to users.
Unified Messaging: Exchange Server allows users to receive voice mail, email, and faxes in their mailboxes. In addition, remote users can access their mailboxes from cell phones and other wireless devices.
Improved IT Experience: Exchange Servers are completely scalable, and include 64-bit performance. There is a simplified graphical user interface (GUI) to make administration easy, and an improved deployment and routing process.
Exchange Server Roles
As a network administrator, you can choose which server roles to install on an Exchange server. Server roles are used to logically group specific features of Exchange together, which helps to simplify installation, and gives you the ability to fully customize your Exchange Server to meet your company's specific needs.The types of server roles include:
Mailbox Server: This server runs on the back end, and hosts mailboxes and public folders.
Unified Messaging Server: This is the middle-tier server that connects a Private Branch Exchange system (PBX, commonly referred to as a phone system) to Exchange 2007.
Client Access Server: This is the middle-tier server that hosts all client protocols, such as Secure Hypertext Transfer Protocol (HTTPS), Post Office Protocol 3 (POP3), Internet Message Access Protocol 4 (IMAP4), and Outlook Anywhere. The Client Access Server can also host Web services.
Hub Transport Server: This server is responsible for routing all mail within the Exchange organization.
Edge Transport Server: This server typically sits on the perimeter of the network topology, and is responsible for routing mail into and out of the Exchange organization.
For the End User
Clients that are using Exchange Server to access their data will typically use Microsoft Outlook, part of the Microsoft Office suite. However, there are alternatives. If a client wishes to connect to their email through a website, they can use Outlook Web Access (OWA). And for Mac users, both Microsoft Entourage and Apple Mail can be used to connect to an Exchange Server.
In Feburary 2016 28,
Microsoft Exchange Server is part of the Microsoft Windows Server line, and is intended to deliver a platform for messaging and collaboration. The primary features of Exchange Server include email, calendaring, contacts and tasks. Exchange Server also provides a platform for mobile and web-based users who need to be able to access their data remotely, as well as support for data storage.
Enhanced Features
Microsoft Exchange Server was first launched in 1996; more recent versions, such as Exchange Server 2007 and recently released Exchange Server 2010, include many enhancements from its original version. Some of these are:
Security: Exchange Server now includes anti-spam and anti-virus filtering, as well as encryption technology. This protects users' data from outside intrusion and corruption.
Data Protection: Exchange Servers can be used in a cluster environment, which replicates the data across several servers and guarantees its availability. In this way, there can be no single point of failure; if one server goes down, the other servers will pick up the slack and continue to provide data to users.
Unified Messaging: Exchange Server allows users to receive voice mail, email, and faxes in their mailboxes. In addition, remote users can access their mailboxes from cell phones and other wireless devices.
Improved IT Experience: Exchange Servers are completely scalable, and include 64-bit performance. There is a simplified graphical user interface (GUI) to make administration easy, and an improved deployment and routing process.
Exchange Server Roles
As a network administrator, you can choose which server roles to install on an Exchange server. Server roles are used to logically group specific features of Exchange together, which helps to simplify installation, and gives you the ability to fully customize your Exchange Server to meet your company's specific needs.The types of server roles include:
Mailbox Server: This server runs on the back end, and hosts mailboxes and public folders.
Unified Messaging Server: This is the middle-tier server that connects a Private Branch Exchange system (PBX, commonly referred to as a phone system) to Exchange 2007.
Client Access Server: This is the middle-tier server that hosts all client protocols, such as Secure Hypertext Transfer Protocol (HTTPS), Post Office Protocol 3 (POP3), Internet Message Access Protocol 4 (IMAP4), and Outlook Anywhere. The Client Access Server can also host Web services.
Hub Transport Server: This server is responsible for routing all mail within the Exchange organization.
Edge Transport Server: This server typically sits on the perimeter of the network topology, and is responsible for routing mail into and out of the Exchange organization.
For the End User
Clients that are using Exchange Server to access their data will typically use Microsoft Outlook, part of the Microsoft Office suite. However, there are alternatives. If a client wishes to connect to their email through a website, they can use Outlook Web Access (OWA). And for Mac users, both Microsoft Entourage and Apple Mail can be used to connect to an Exchange Server.
In Feburary 2016 28,
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