How to obtain hostname from IP address in Linux?

Today, I fell in need of identifying the host name (also termed as ‘DNS name‘) based on the IP address for one of my Linux Box. My first try was using 'ping -a' command. But that failed to satisfy my requirement.

Domain names, arranged in a tree, cut into zon...
Image via Wikipedia

If you ever come across the situation where 'ping -a' does not provide you with the host name of the box, then you can try any of the below mentioned methods to satisfy the requirement.

Method 1: Using the 'host' command

One of the simplest way to retrieve host name from IP address is employing the 'host' command provided by GNU/Linux.
Syntax for the host command: $>host <ip-address> <nameserver>
Example:

testhost:~ # host 209.85.231.104
104.231.85.209.in-addr.arpa domain name pointer maa03s01-in-f104.google.com.
testhost:~ #

Method 2: Using the 'nslookup' command

nslookup is a command used to query the Internet Domain Name servers.

Example:
nslookup 209.85.231.104
Server:  72.163.128.140
Address: 72.163.128.140#53


Non-authoritative answer:
104.231.85.209.in-addr.arpa    name = maa03s01-in-f104.google.com.


Authoritative answers can be found from:
231.85.209.in-addr.arpa    nameserver = ns1.google.com.
231.85.209.in-addr.arpa    nameserver = ns3.google.com.
231.85.209.in-addr.arpa    nameserver = ns4.google.com.
231.85.209.in-addr.arpa    nameserver = ns2.google.com.
ns3.google.com    internet address = 216.239.36.10
ns4.google.com    internet address = 216.239.38.10
ns2.google.com    internet address = 216.239.34.10
ns1.google.com    internet address = 216.239.32.10

Method 3: Using the 'dig' command
As per the Linux man pagedig (domain information groper) is a flexible tool for interrogating DNS name servers. It performs DNS lookups and displays the answers that are returned from the name server(s) that were queried.

Disclaimer

All data and information provided on this site is for informational purposes only. sks8.wordpress.com or skumar.co.nr makes no representations as to accuracy, completeness, currentness, suitability, or validity of any information on this site and will not be liable for any errors, omissions, or delays in this information or any losses, injuries, or damages arising from its display or use. All information is provided on an as-is basis. Any trademarks, if at all displayed on this blog belong to their respective owners.

Reblog this post [with Zemanta]

Description of HTML Response Status Codes returned from a Server

1xx status codes

100 (Continue) The requestor should continue with the request. The server returns this code to indicate that it has received the first part of a request and is waiting for the rest.
101 (Switching protocols) The requestor has asked the server to switch protocols and the server is acknowledging that it will do so.

2xx status codes indicate that the server successfully processed the request.

200 (Successful) The server successfully processed the request. Generally, this means that the server provided the requested page. If you see this status for your robots.txt file, it means that Googlebot retrieved it successfully.
201 (Created) The request was successful and the server created a new resource.
202 (Accepted) The server has accepted the request, but hasn’t yet processed it.
203 (Non-authoritative information) The server successfully processed the request, but is returning information that may be from another source.
204 (No content) The server successfully processed the request, but isn’t returning any content.
205 (Reset content) The server successfully proccessed the request, but isn’t returning any content. Unlike a 204 response, this response requires that the requestor reset the document view (for instance, clear a form for new input).
206 (Partial content) The server successfully processed a partial GET request.

3xx status codes indicates that further action is needed to fulfill the request. Most often, these status codes are used for redirection.

300 (Multiple choices) The server has several actions available based on the request. The server may choose an action based on the requestor (user agent) or the server may present a list so the requestor can choose an action.
301 (Moved permanently) The requested page has been permanently moved to a new location. When the server returns this response (as a response to a GET or HEAD request), it automatically forwards the requestor to the new location.
302 (Moved temporarily) The server is currently responding to the request with a page from a different location, but the requestor should continue to use the original location for future requests. This code is similar to a 301 in that for a GET or HEAD request, it automatically forwards the requestor to a different location.
303 (See other location) The server returns this code when the requestor should make a separate GET request to a different location to retrieve the response. For all requests other than a HEAD request, the server automatically forwards to the other location.
304 (Not modified) The requested page hasn’t been modified since the last request. When the server returns this response, it doesn’t return the contents of the page.
305 (Use proxy) The requestor can only access the requested page using a proxy. When the server returns this response, it also indicates the proxy that the requestor should use.
307 (Temporary redirect) The server is currently responding to the request with a page from a different location, but the requestor should continue to use the original location for future requests. This code is similar to a 301 in that for a GET or HEAD request, it automatically forwards the requestor to a different location.

4xx status codes indicate that there was likely an error in the request which prevented the server from being able to process it.

400 (Bad request) The server didn’t understand the syntax of the request.
401 (authentication error) The page requires authentication.
403 (Forbidden) The server is refusing the request.
404 (Not found) The server can’t find the requested page. For instance, the server often returns this code if the request is for a page that doesn’t exist on the server.
405 (Method not allowed) The method specified in the request is not allowed.
406 (Not acceptable) The requested page can’t respond with the content characteristics requested.
407 (Proxy authentication required) This status code is similar to 401 but specifies that the requestor has to authenticate using a proxy. When the server returns this response, it also indicates the proxy that the requestor should use.
408 (Request timeout) The server timed out waiting for the request.
409 (Conflict) The server encountered a conflict fulfilling the request. The server must include information about the conflict in the response. The server might return this code in response to a PUT request that conflicts with an earlier request, along with a list of differences between the requests.
410 (Gone) The server returns this response when the requested resource has been permanently removed. It is similar to a 404 (Not found) code, but is sometimes used in the place of a 404 for resources that used to exist but no longer do.
411 (Length required) The server won’t accept the request without a valid Content-Length header field.
412 (Precondition failed) The server doesn’t meet one of the preconditions that the requestor put on the request.
413 (Request entity too large) The server can’t process the request because it is too large for the server to handle.
414 (Requested URI is too long) The requested URI (typically, a URL) is too long for the server to process.
415 (Unsupported media type) The request is in a format not support by the requested page.
416 (Requested range not satisfiable) The server returns this status code if the request is for a range not available for the page.
417 (Expectation failed) The server can’t meet the requirements of the Expect request-header field.

5xx status codes indicate that the server had an internal error when trying to process the request. These errors tend to be with the server itself, not with the request.

500 (Internal server error) The server encountered an error and can’t fulfill the request.
501 (Not implemented) The server doesn’t have the functionality to fulfill the request. For instance, the server might return this code when it doesn’t recognize the request method.
502 (Bad gateway) The server was acting as a gateway or proxy and received an invalid response from the upstream server.
503 (Service unavailable) The server is currently unavailable (because it is overloaded or down for maintenance). Generally, this is a temporary state.
504 (Gateway timeout) The server was acting as a gateway or proxy and didn’t receive a timely request from the upstream server.
505 (HTTP version not supported) The server doesn’t support the HTTP protocol version used in the request.

Disclaimer

All data and information provided on this site is for informational purposes only. sks8.wordpress.com or skumar.co.nr makes no representations as to accuracy, completeness, currentness, suitability, or validity of any information on this site and will not be liable for any errors, omissions, or delays in this information or any losses, injuries, or damages arising from its display or use. All information is provided on an as-is basis. Any trademarks, if at all displayed on this blog belong to their respective owners.

Reblog this post [with Zemanta]