Windows Hosts File
Angelo Dearring
Windows includes a local "Hosts" file that contains domain names and matching IP addresses, acting as a map to identify and locate hosts on IP networks. Every time you visit a website, your computer will check the hosts file first to see which IP address it connects to. If the information is not there, your internet service provider will look into the DNS for the resources to load the site.
The Hosts File Editor provides a convenient way to edit the hosts file configuration. This can be useful for scenarios like migrating a website to a new hosting provider or domain name, which may take a 24-48 hour period of downtime. Creating a custom IP address to associate with your domain using the hosts file can enable you to see how it will look on the new server.
Hosts File Editor creates a backup of the hosts file before editing session. The backup files are located near the hosts file in %SystemRoot%/System32/drivers/etc named hosts_PowerToysBackup_YYYYMMDDHHMMSS.
The Hosts file is used by the operating system to map human-friendly hostnames to numerical Internet Protocol (IP) addresses which identify and locate a host in an IP network. The hosts file is one of several system resources that address network nodes in a computer network and is a common part of an operating system's IP implementation.
The Hosts file contains lines of text consisting of an IP address in the first text field followed by one or more host names. Each field is separated by white space (Tabs are often preferred for historical reasons, but spaces are also used). Comment lines may be included, and they are indicated by a hash character (#) in the first position of such lines. Entirely blank lines in the file are ignored.
I am trying to identify "windows hosts" that are logging to my Splunk indexer. Unfortunately, neither the hosts/server names nor anything like IP address subnet, have a pattern that uniquely identify my windows hosts for using a REGEX. I have looked at the metadata function and that does give me list of hosts, but that does not help because I cannot tell which hosts are "windows".
Here is what I have tried so far:
1. I created an eventtype=windows_hosts based on the following search: (sourcetype=windowsupdate OR sourcetype="WinEventLog:Application" OR sourcetype="WinEventLog:Security" OR sourcetype="WinEventLog:System") dedup host table host
2. This gives me the list I want, but the list is now derived by searching through the events which I am sure will be a lot of overhead depending on the timeframe I use.
You can generate a lookup table which contains the hosts which you have seen Windows data for in the past. This search will merge them into a lookup, so you could schedule it to run each day or another appropriate time period.
Thanks Cvajs. Acutally, I do have all the windows servers going to "windows-only" indexes. However, my question is what is the most efficient way of reporting on those hosts? I can do the search you mentioned but searches through all the events again to extract the host field. The gist of my question was whether I could get Splunk to dynamically maintain a list of windows-hosts at indexing time rather than at search time. But in retrospect that might not make much sense.
well, your question to me sounds like you have disparate types of sources being dumped into the same index and now you wish to search the index for just windows systems. can you configure Splunk to dump all of your windows sources into a "windows_only" index? if you do this then you dont need a custom eventtype, you just search the index directly as it will return data that is just windows related, etc. now your search becomes "index=windows_only table host", or, if the user role is pinned to windows_only then all you need is "table host".
I got tricked thinking that the site serves traffic via where in fact the URL is using a subdomain e.g. https://www.example.comIn that case just add one more record to the hosts file with www.example.com like below:
As the internet grew, so did the length and complexity of the hosts files. Also, each hosts file only worked for the computer it was on, and keeping them in sync with the changes in hostnames and IP addresses became a huge pain.
Early on, a central hosts file was manually maintained and shared by the Stanford Research Institute. This system lead to the invention of domains and top level domains like .com and .edu, Whois, and it became increasingly automated.
Note that everything is commented out with # characters, meaning that nothing is actually being read from the hosts file. Modern versions of Windows include a sort of DNS system already, so if you visit localhost it'll automatically redirect you to 127.0.0.1.
Basically, this program Acrylic works as a DNS proxy for your local machine. Just point your Local Area Connection to 127.0.0.1, then edit the AcrylicHosts.txt in a very similar manner to the regular hosts file -- only with wildcards!
secondly, you have to get control over the result of a request to dns. one option is to use your own dns-resolving on your router (dnsmasq, dnscache+tinydns, bind, whatever, see quack's comment) and tweak it or to use a dns-resolver on windows which you can control as you want.
No, changes to the hosts file are immediate. However, your browser cache settings may sometimes make it appear that changes you have made have not taken effect depending on what you are doing, so it's always best to clear your browser's cache if it appears a change did not take effect.
Depending on your wato folder structure, your server naming convention and the amount of hosts, it might not be such a big deal to add labels like os:windows and os:linux to your servers.
In wato you can search for patterns and do a bulk assign on these hosts.
When I save the file and try to reach the host with a browser, I'm getting a "host not found" error. I tried setting the "read-only" file attribute to the hosts file -- same result. I tried flushing the DNS cache, but nothing changes.
Are there specific requirements or rules to follow to ensure that Windows can always properly detect a change to the hosts file, read and parse its contents, and immediately take into account changes when using a browser or ping to test via the command-line?
In this article I present a couple of simple PowerShell scripts which will modify the hosts file on one (or more) Windows machines, so that you can route traffic destined for certain domains to specific IP addresses with minimal fuss. The scripts do this by adding (or removing) entries to (or from) the hosts file and they do this idempotently[1], so you don't need to write any checks when adding or removing. In other words, when you add a host to the hosts file, it won't add it if it's already there.
Additionally, there's an extra script which enables you to copy your modified hosts file to multiple machines. This needs to be used with extreme caution (although it does make a backup of the remote hosts file), but is useful if you are trying to get precisely the same hosts file onto several machines in one step.
If you need to override DNS settings and route traffic for certain domains to specific IP addresses of your choosing then, if you don't want to mess around with DNS servers and/or proxies, the easiest way is to modify your hosts file. But what if you're dealing with a cluster of machines? What if you're not sure if you've already added some of the hosts entries? What if you need a script to automate the process? Don't worry, I've got you covered.
There are various reasons (not all of them nefarious) why you might want to edit your Windows hosts file to change the routing of certain domains. These scripts are a safe, easy way to do that, especially in the case where you need to update multiple machines at the same time. A little while ago, I used a somewhat less-sophisticated version of these scripts in real life to fix a major problem. I hope they can help you in a somewhat less stressful scenario.
On PowerShell v3.0, there is a bug that limits the amount of memory available to the WinRM service. Use the Install-WMF3Hotfix.ps1 script to install a hotfix on affected hosts as part of the system bootstrapping or imaging process. Without this hotfix, Ansible fails to execute certain commands on the Windows host.
Windows borrowed a lot of patterns from BSD systems during the implementation of the network. One of the most important modules of the operating system that supports addressing in computer networks is the hosts file. Its role is to translate friendly domain names into their numerical equivalents, i.e. IP addresses. Thanks to this it is easy to identify the computer in the network, without the need to remember complicated numbers.
Editing hosts file allows you to quickly and easily connect to hosting or server if you do not have an active or directed domain yet. This is especially useful when migrating services or testing a new website.
A hosts file is a text file containing an IP address on each line, as well as one or more domain names of the host, which can be separated by spaces or tabs. Lines beginning with hash are comments (and are therefore ignored).
However, you can simplify everything and take advantage of the fully graphical tool called Hosts File Editor. This is a small application that edits the hosts file without having to do the process described above. Below we present the appearance:
The computer file hosts is an operating system file that maps hostnames to IP addresses. It is a plain text file. Originally a file named HOSTS.TXT was manually maintained and made available via file sharing by Stanford Research Institute for the ARPANET membership, containing the hostnames and address of hosts as contributed for inclusion by member organizations. The Domain Name System, first described in 1983 and implemented in 1984,[1] automated the publication process and provided instantaneous and dynamic hostname resolution in the rapidly growing network. In modern operating systems, the hosts file remains an alternative name resolution mechanism, configurable often as part of facilities such as the Name Service Switch as either the primary method or as a fallback method.
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