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- The core component of application delivery is an application delivery controller (ADC), which is an advanced load balancer sitting in front of your application servers and directing client requests to your servers in a manner that maximizes performance and capacity utilization. Further, an ADC sends requests only to application servers that are.
- The client invokes one of the available methods of the server. Like methods in a class library, the methods of a Web service can accept an arbitrary number of input parameters, and can optionally return a result. The Web services standard spells out in great detail how a client can invoke a Web service method from a server.
An ArcGIS Server web service represents a GIS resource—such as a map or image—that is located on an ArcGIS Server site and is made available to client apps such as Map Viewer. You can add ArcGIS Server web services to ArcGIS Online to use them in apps throughout ArcGIS. I've created Web Services in.Net 3.5 & Consumed those Web Services in a Client Web Application. Now i want to Host the WebService in IIS 5.1. Pls Help me to do this!! I'm using VS 2010, Wndows XP Service Pack 3, IIS 5.1. And I'm very new to.net. Thanks in Advance!! Web Services Description Language (WSDL) is an XML-based file that basically tells the client application what the web service does. The WSDL file is used to describe in a nutshell what the web service does and gives the client all the information required to connect to the web service and use all the functionality provided by the web service.
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- Web Services Resources
- Selected Reading
Web Services Questions and Answers has been designed with a special intention of helping students and professionals preparing for various Certification Exams and Job Interviews. This section provides a useful collection of sample Interview Questions and Multiple Choice Questions (MCQs) and their answers with appropriate explanations.
SN | Question/Answers Type |
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1 | Web Services Interview Questions This section provides a huge collection of Web Services Interview Questions with their answers hidden in a box to challenge you to have a go at them before discovering the correct answer. |
2 | Web Services Online Quiz This section provides a great collection of Web Services Multiple Choice Questions (MCQs) on a single page along with their correct answers and explanation. If you select the right option, it turns green; else red. |
3 | Web Services Online Test If you are preparing to appear for a Java and Web Services Framework related certification exam, then this section is a must for you. This section simulates a real online test along with a given timer which challenges you to complete the test within a given time-frame. Finally you can check your overall test score and how you fared among millions of other candidates who attended this online test. |
4 | Web Services Mock Test This section provides various mock tests that you can download at your local machine and solve offline. Every mock test is supplied with a mock test key to let you verify the final score and grade yourself. |
This chapter introduces the Web services security concepts. It is divided into the following sections:
For an introduction to general Web service concepts, see 'What are Web Services' in Introducing Web Services.
Securing Web Services
Because of its nature (loosely coupled connections) and its use of open access (mainly HTTP), SOA implemented by Web services adds a new set of requirements to the security landscape. Web services security includes several aspects:
- Authentication—Verifying that the user is who she claims to be. A user's identity is verified based on the credentials presented by that user, such as:
- Something one has, for example, credentials issued by a trusted authority such as a passport (real world) or a smart card (IT world).
- Something one knows, for example, a shared secret such as a password.
- Something one is, for example, biometric information.
Using a combination of several types of credentials is referred to as 'strong' authentication, for example using an ATM card (something one has) with a PIN or password (something one knows). - Authorization (or Access Control)—Granting access to specific resources based on an authenticated user's entitlements. Entitlements are defined by one or several attributes. An attribute is the property or characteristic of a user, for example, if 'Marc' is the user, 'conference speaker' is the attribute.
- Confidentiality, privacy—Keeping information secret. Accesses a message, for example a Web service request or an email, as well as the identity of the sending and receiving parties in a confidential manner. Confidentiality and privacy can be achieved by encrypting the content of a message and obfuscating the sending and receiving parties' identities.
- Integrity, non repudiation—Making sure that a message remains unaltered during transit by having the sender digitally sign the message. A digital signature is used to validate the signature and provides non-repudiation. The timestamp in the signature prevents anyone from replaying this message after the expiration.
Web services security requirements also involve credential mediation (exchanging security tokens in a trusted environment), and service capabilities and constraints (defining what a Web service can do, under what circumstances).
In many cases, Web services security tools such as Oracle WSM rely on Public Key Infrastructure (PKI) environments. A PKI uses cryptographic keys (mathematical functions used to encrypt or decrypt data). Keys can be private or public. In an asymmetric cipher model, the receiving party's public key is used to encrypt plaintext, and the receiving party's matching private key is used to decrypt the ciphertext. Also, a private key is used to create a digital signature by signing the message, and the public key is used for verifying the signature. Public-key certificates (or certificates, for short) are used to guarantee the integrity of public keys.
Hat Tip 1 3 – Http Web Services Client Asks To Be
Web services security requirements are supported by industry standards both at the transport level (Secure Socket Layer) and at the application level relying on XML frameworks.
Hat Tip 1 3 – Http Web Services Client Asks Job
For more information about the specifications, standards, and security tokens supported by Web services, see Appendix A, 'Web Service Security Standards.'
Note:
Oracle has been instrumental in contributing to emerging standards, in particular the specifications hosted by the OASIS Web Services Secure Exchange technical committee.Transport-level Security
Secure Socket Layer (SSL), otherwise known as Transport Layer Security (TLS), the Internet Engineering Task Force (IETF) officially standardized version of SSL, is the most widely used transport-level the data is not protected. This makes the environment vulnerable to attacks in multi-step transactions. (SSL provides point-to-point security, as opposed to end-to-end security.)
Application-level Security
Application-level security complements transport-level security. Application-level security is based on XML frameworks defining confidentiality, integrity, authenticity; message structure; trust management and federation.
Data confidentiality is implemented by XML Encryption. XML Encryption defines how digital content is encrypted and decrypted, how the encryption key information is passed to a recipient, and how encrypted data is identified to facilitate decryption.
Data integrity and authenticity are implemented by XML Signature. XML Signature binds the sender's identity (or 'signing entity') to an XML document. Signing and signature verification can be done using asymmetric or symmetric keys.
Signature ensures non-repudiation of the signing entity and proves that messages have not been altered since they were signed. Message structure and message security are implemented by SOAP and its security extension, WS-Security. WS-Security defines how to attach XML Signature and XML Encryption headers to SOAP messages. In addition, WS-Security provides profiles for 5 security tokens: Username (with password digest), X.509 certificate, Kerberos ticket, Security Assertion Markup Language (SAML) assertion, and REL (rights markup) document. Calcbot the intelligent calculator and unit converter 1 0 5.
The SOAP envelope body includes the business payload, for example a purchase order, a financial document, or simply a call to another Web service. SAML is one of the most interesting security tokens because it supports both authentication and authorization. SAML is an open framework for sharing security information on the Internet through XML documents. SAML includes 3 parts:
- SAML Assertion—How you define authentication and authorization information.
- SAML Protocol—How you ask (SAML Request) and get (SAML Response) the assertions you need.
- SAML Bindings and Profiles—How SAML assertions ride 'on' (Bindings) and 'in' (Profiles) industry-standard transport and messaging frameworks.
The full SAML specification is used in browser-based federation cases. However, web services security systems such as Oracle WSM only use SAML assertions. The protocol and bindings are taken care of by WS-Security and the transport protocol, for example HTTP.
SAML assertions and references to assertion identifiers are contained in the WS-Security Header element, which in turn is included in the SOAP Envelope Header element (described in the WS-Security SAML Token Profile). The SAML security token is particularly relevant in situations where identity propagation is essential.
Web Service Security Requirements
The following summarize the Web service security requirements:
- The use of transport security to protect the communication channel between the Web service consumer and Web service provider.
- Message-level security to ensure confidentiality by digitally encrypting message parts; integrity using digital signatures; and authentication by requiring username, X.509, or SAML tokens.
Oracle Web Services Manager (WSM) is designed to define and implement Web services security in heterogeneous environments, including authentication, authorization, message encryption and decryption, signature generation and validation, and identity propagation across multiple Web services used to complete a single transaction.
How Oracle Fusion Middleware Secures Web Services and Clients
Hat Tip 1 3 – Http Web Services Client Asks Interview
Figure 2-1 shows an Oracle Fusion Middleware application that demonstrates some common interactions between Web services and their clients. How security is managed at each step in the process is explained following the figure.
The Oracle WSM Policy Manager (labeled as OWSM in Figure 2-1) is the security linchpin for Oracle Fusion Middleware Web services and SOA applications. For more information about how the Oracle WSM Policy Manager manages the policy framework, see Chapter 3, 'Understanding Oracle WSM Policy Framework.'
Figure 2-1 Example of Oracle Fusion Middleware Application
Description of 'Figure 2-1 Example of Oracle Fusion Middleware Application'
As shown in the previous figure, there are two types of policies that can be attached to Web services: Oracle WSM policies and WebLogic Server polices. For more information, see Table 1-1, 'Types of Web Service Policies'.
The following describes in more detail the Web service and client interactions called out in the previous figure, and how security is managed at each step in the process. As noted in the figure, security is managed using both Oracle WSM policies and WebLogic Web service policies.
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- At design time, you attach Oracle WSM and WebLogic Web service policies to applications programmatically using your favorite IDE, such as Oracle JDeveloper.Alternatively, at deployment time you attach policies to SOA composites, ADF, and WebCenter applications using the Oracle Enterprise Manager Fusion Middleware Control, and to WebLogic Web services (Java EE) using the WebLogic Server Administration Console (not shown in the figure).Note: Policies that are attached to WebLogic Web services at design time cannot be detached at deployment time. You can only attach new policies.
- A user logs in to the ADF Web application. Iconjar all your icons in one place 1 3 1.The user may be internal or external to Company A.
- Using a Web service data control, the ADF Web application accesses a service, such as a WebLogic Web service, a SOA composite application, or an ADF Business Component.At the Web service client side, Oracle WSM intercepts the SOAP message request to the service, injects the relevant tokens, and signs and encrypts the message, as required by the attached policies.At the Web service side, Oracle WSM intercepts the SOAP message request to the service, extracts the tokens, and verifies the client's credentials against an identity management infrastructure (for example, a file, an LDAP-compliant directory, or Oracle Access Manager), as required by the attached policies.
- Interactions with the SOA service components (shown in the figure) include:
- The SOA service component accesses an ADF Business Component to query or update tables in a database.
- A WebCenter client access the SOA service component to process a customer request.
- The SOA service component accesses the Web service internal to Company A to accomplish a specific task.
- The SOA service component accesses a Web service via an external provider (Company B) to accomplish a specific task. As long as you know the URL that identifies the WSDL document, you can access the Web service.
Again, at the Web service client side, Oracle WSM intercepts the SOAP message request to the service, injects the relevant tokens, and signs and encrypts the message, as required by the attached policies.At the Web service side, Oracle WSM intercepts the SOAP message request to the service, extracts the tokens, and verifies the client's credentials against an identity management infrastructure (for example, a file, an LDAP-compliant directory, or Oracle Access Manager), as required by the attached policies. - A client accesses a WebLogic Java EE Web service.In this case, components in a larger composite application interact with the WebLogic Web service. An Oracle WSM policy is used to secure the WebLogic JAX-WS Web service client. A WebLogic Web service policy is used to secure the WebLogic JAX-RPC service client.