How many subdomains?

[Newmedia]

How many subdomains can you have on a single domain?

Is there a limit?

And what is the best use of subdomains? Ie your blog? Mobile site?

 

[10032012]

I think the maximum size of a domain name (including subdomain) is limited to the infamous-number-in-computing 255...

So theoretically is depends how large the domain name is in the first place, once you have that... its all alphanumerical chars in any combination with some others including - and . (such as different levels).

Some domain registrars and hosts will obviously limit the number allowed, but technically... a domain can have millions of subdomains.

 

[lynxus]

I think the maximum size of a domain name (including subdomain) is limited to the infamous-number-in-computing 255...

So theoretically is depends how large the domain name is in the first place, once you have that... its all alphanumerical chars in any combination with some others including - and . (such as different levels).

Some domain registrars and hosts will obviously limit the number allowed, but technically... a domain can have millions of subdomains.

Na , You can have almost as many as you want. Way more than 255.

255 is pretty much the max "length" a domain can be ( the amount of chars in the address bar , But you can have more.. Its just some browsers may not be able to use it.. )


However the limit to subdomains is solely dependant on the DNS server. ( How many subdomains can it hold in the zone file )

BIND can handle something like 16,777,216 subdomains and according to google windows dns servers can do 20k per zone.

So to be safe.
up to 20k would be easy. More than that and you would need to use bind as the dns resolver.

 

[astutiumRob]

Max length of an actual domain is (currently) 63 characters including the gTLD/ccTLD with shorter restrictions for some country domains

Max length is you expect it to work in all browsers/forms/software including prefix is also 63 or you start to get less and less possible uses for it

Max number of them - very much depends on if/when/how the dns provider, registry, registrar and host implement DNSSEC - currently there is no preset limit, but you'll find >254 wont work once dnssec is rolled out.

 

[Newmedia]

Na , You can have almost as many as you want. Way more than 255.

255 is pretty much the max "length" a domain can be ( the amount of chars in the address bar , But you can have more.. Its just some browsers may not be able to use it.. )


However the limit to subdomains is solely dependant on the DNS server. ( How many subdomains can it hold in the zone file )

BIND can handle something like 16,777,216 subdomains and according to google windows dns servers can do 20k per zone.

So to be safe.

up to 20k would be easy. More than that and you would need to use bind as the dns resolver.

I was expecting an answer along the lines of You can have not 20 subdomains to 1 domain not 20K!!!

Seriously, how many would a standard hosting plan allow or are they pretty flexible?

 

[lynxus]

I was expecting an answer along the lines of You can have not 20 subdomains to 1 domain not 20K!!!

Seriously, how many would a standard hosting plan allow or are they pretty flexible?

Honestly, Who knows .. Only your host knows how many their servers support. ( or how many subdomains they allow.. )

Cant say ive ever "reached" a limit before.

 

[Dark-Kni]

So what's basically the purpose of having a sub domain?

 

[frida_adams]

The number of sub-domains shouldn't be a problem.

 

[10032012]

So what's basically the purpose of having a sub domain?

A subdomain is a third level domain... the purpose is to enable a URL for another computer (i.e. computer1.domain.com and computer2.domain.com) with a different IP although most subdomains are done by VirtualHost so are on the same physical machine under the same IP (of course IPs can be assigned or different websites on same physical machine also).

It allows you to set up different websites under the same domain but unlike a subdirectory which is treated as part of the same website, it acts as a separate website. These could be for a variety of reasons such as hosting different services on different hosts (you cant with a subdirectory), SEO reasons (pros and cons) and differentiation between the company website and user websites (many free services like geocities used subdirectories however).

(Of course many physical websites are clustered so www.google.com for example will not be one physical machine although appears to be. This is getting more common with all the cloud services even for websites which doesn't really particularly require more than one physical machine / high availability and resilience.)

You could argue why a subdomain over say another domain name... subdomains are usually favoured as they feel a part of the main domain name over a completely different website address. For example support.microsoft.com feels part of Microsoft (as on their flagship corporate website) than microsoftsupport.com would... which could in effect be owned and operated by someone completely different.

 

[pcproblems]

My package with 1&1 allows 50 sub domains but their business package allows 'unlimited' sub domains

 

[jimi58]

No matter
how many sub domain

 

[william04]

New pages on an existing site will likely get listed and ranked quicker than a new site.
But it does depend to some extent how old the 'existing site' is, and what else is on the site. Related content, some say, will rank quicker - and better.

To be comparable with a subdomain, don't plant the new content to deep. But there is no reason why site.com/newstuff shouldn't do as well as newstuff.site.com - and better, if there's existing content, existing incomng links and existing ranking at site.com.

But you will need to build in good navigation so the new stuff really is part of the existing site, in order to gain the 'shared domain' benefits.

 

[10032012]

New pages on an existing site will likely get listed and ranked quicker than a new site.
But it does depend to some extent how old the 'existing site' is, and what else is on the site. Related content, some say, will rank quicker - and better.

To be comparable with a subdomain, don't plant the new content to deep. But there is no reason why site.com/newstuff shouldn't do as well as newstuff.site.com - and better, if there's existing content, existing incomng links and existing ranking at site.com.

But you will need to build in good navigation so the new stuff really is part of the existing site, in order to gain the 'shared domain' benefits.

As a rule of thumb, use subdomains if you want numerous listings (i.e. 2 subdomains can give 4 results out of 10) or subdirectories etc. (if you want to be limited to 1-3 typically 2, out of 10). Google isn't completely stupid so will rarely allow 2 or more subdomains in a single search result page to prevent this abuse.

Likewise, 10 directories is better for SEO then sticking each directory as a subdomain. Of course you can undertake various SEO to counter this. Google is much slower at picking up new subdomains than it is new directories (whether actual or virtual) but of course all depends on backlinks etc

 

[william04]

Good information mate !

 

[vishalchadha53]

Not really a theoretical limit. Varies by host. With the first tier hosting companies, it will probably be a number higher than what you would need.