DNS lookup, caching in Sterling B2B Integrator.

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Author: Manisha Khond, IBM Cognitive Engagement, Watson Supply Chain.

Let us go through the basic knowledge on DNS.

What is DNS?

• DNS stands for domain name system, which is the database responsible for storing all of the information pertaining to IP addresses and domain names.

What is Domain name?

• A domain name is actually a lingual representation of an IP address, which is a series of numbers separated by dots.

What is DNS lookup?

• It is the process of obtaining IP address for the domain name.

DNS lookup and the effect on performance:

• When the user’s browser requests a web page from the server, it first asks the domain name system (DNS) to map the domain name to an IP address. Depending on caching, remoteness, and other factors, this lookup process can perform poorly. Since every component on the web page goes through the same lookup process, DNS performance can become an important consideration. In a more realistic case, the lookup process can have a significant impact on overall performance, which makes our website seem slow.

DNS caching:

• Your DNS cache stores the locations (IP addresses) of web servers that contain web pages which you have recently viewed.

Reverse DNS lookup:

• Reverse DNS lookup or reverse DNS resolution is the determination of a domain name that is associated with a given IP address.

Are there any tools available to perform DNS lookup or perform DNS troubleshooting?

• Operating system provides the commands for DNS lookup. Please refer to your Operating system documentation. Commonly used commands on Linux and Windows are: nslookup ipconfig, ping, host.

Information pertaining to Sterling B2B Integrator:

How to perform DNS lookup in less secure zone?

• Sterling B2B Integrator has the functionality to allow DNS lookup on Perimeter Server. Perimeter Server is in the less secure zone than the host with Sterling B2B Integrator installation. This functionality is useful when your company security policy does not allow DNS Lookup in secured network.

How do you implement DNS lookup on Perimeter Server?

• It requires modification to Sterling B2B Integrator property file and restarting Sterling B2B Integrator. Please check Sterling B2B Integrator documentation on instructions to implement DNS lookup on Perimeter Server.

Does Sterling Integrator support DNS Caching?

• Sterling B2B Integrator supports DNS Caching. This requires modifications to Sterling Integrator properties files and also java.security file. Please check IBM knowledge base to find the instructions.

Does Sterling B2B Integrator Adapters perform reverse DNS lookup?

• There are certain adapters in Sterling B2B Integrator that perform reverse DNS lookup. This is to perform additional authentication.

Do you have further questions?

Please refer to comments section of the blog.