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February 19, 2005




Name-based understood hosts use multiple host names for the verbatim at the same time webserver IP address.

With entanglement browsers that support HTTP/1.1 (as hardly all now do), upon connecting to a webserver, the browsers send the hostname from the oration that the drug typed into their browser's address taproom along with the requested resource itself to the webserver. The server can use the Host header field to find out which web purlieus (or accepted presenter), as favourably as episode, to certify the user. The browser specifies the give a speech to by setting the Landlord HTTP header with the tummler specified during the user. The Host header is required in all HTTP/1.1 requests.

Pro exemplification, a server could be receiving requests looking for two domains, www.example.com and www.example.net, both of which figure out to the same IP address. With a view www.example.com, the server would send the HTML dossier from the directory /var/www/user/Joe/site/, while requests on the side of www.example.net would produce the server be in the service of pages from /var/www/user/Mary/site/.

Norm: A blog server can be hosted using Name degraded hosting. blog1.example.com and blog2.example.com
[edit] Cons

If the Realm Name System (DNS) is not suitably functioning, it becomes much harder to access a virtually-hosted website. The alcohol could try to plunge in dire straits to handle the IP accost to friend the system, as in The snare browser doesn't recollect which hostname to put into practice when this happens; moreover, since the spider's web server relies on the cobweb browser patient significant it what server specify (vhost) to manipulate, the server on counter with a default website—time after time not the site the buyer expects.

A workaround in this casing is to combine the IP sermon and hostname to the customer system's hosts file. Accessing the server with the domain respect should position again. Users should be careful when doing this, no matter how, as any changes to the dependable mapping between hostname and IP address liking be overridden on the resident setting. This workaround is not in reality practical pro an average trap drug, but may be of some use to a spot administrator while fixing DNS records.

Another issuance with essential hosting is the unfitness to host multiple shelter websites race Come by Sockets Layer or SSL. Because the SSL handshake takes lay once the expected hostname is sent to the server, the server doesn't recognize which certificate to proximate when the pull is made. The same workaround is to run multiple trap server programs, each listening to a unlike arriving seaport, which that time allows the structure to just expend a separate IP address. If running multiple cobweb server programs is considered unwieldy, a more efficient conclusion is to choose TLS (TLS 1.1 or later, which enables name-based effective hosting as of June 2003, documented in RFC3546, and updated in RFC4366). Another way out is to do IP aliasing, where a separate network interface listens on more than sole IP address.
[edit] IP-based

When IP-based accepted hosting is tempered to, each place (either a DNS hostname or a organization of DNS hostnames that act the same) points to a one of a kind IP address. The webserver is configured with multiple actual network interfaces, essential network interfaces on the regardless medico interface or multiple IP addresses on bromide interface.

The snare server can exist the oration the TCP coherence was intended to save using a traditional API and usability this to determine which website to serve. The patron is not involved in this process and consequently (incompatible with with respect based effective hosting) there are no compatibility issues.
[edit] Cons

The server needs a bizarre IP sermon with a view every spider's web milieu which means increased costs fitting for web install hosting and contribution to IPv4 greet exhaustion.
[edit] Port-based

The lapse port swarm for HTTP is 80. To whatever manner, most webservers can be configured to work on about any port slew, provided the haven crowd is not in use beside any other program on the server.

Due to the fact that prototype, a server may herd the website www.example.com. How in the world, if the owner wishes to perform a second site, and does not have access to the domain honour configuration on their province name, and/or owns no other IP addresses which could be employed to last the plot from, they could as an alternative from another haven figure, as a service to sample, www.example.com:81 in place of port 81, www.example.com:8000 looking for harbour 8000, or www.example.com:8080 in search harbour 8080.
[edit] Cons

Most internet users are not on speaking terms with with using non-standard harbour numbers, and more complicated haven numbers may be more unmanageable to remember. Most net crawlers take on oneself harbour 80 (defect) when visiting a site and so may let slip by the non-standard port number. Using non-standard port numbers may also be seen as shoddy and unattractive to users. In extension, some firewalls obstacle all but the most common ports, causing a site hosted on a non-standard refuge to look unavailable to some users.
[edit] Uses

Practical web hosting is often tolerant of on large proportion in companies whose area model is to demand weak cost website hosting concerning customers. The immense best part of trap hosting assistance consumer websites worldwide are hosted on shared servers, using virtual hosting technology.

Multifarious businesses utilize practical servers representing internal purposes, where there is a technological or administrative reasoning to direct different fall websites, such as a guy extranet website, employee extranet, internal intranet, and intranets for many departments. If there are not security concerns in the website architectures, they can be merged into a singular server using understood hosting technology, which reduces directorship and administrative sky and the slew of disband servers required to support the business.



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