DNS Subdomain Name Length

[ecsaltz]

I have found that the subdomain name length can't exceed
17 characters. I.E., subdomain.domain.com. When I have a
Win2K DNS server with a subdomain 18 characters or
longer, I can't ping the DNS name without getting
a "can't find" error from a PC on the same internal
network that is using the DNS of that server. But, from
outside on the Internet, I can ping without any problems.
Anyone have any ideas how to get around this problem?
Thanks.

 

[Ace Fekay [MVP]]

In

I have found that the subdomain name length can't exceed
17 characters. I.E., subdomain.domain.com. When I have a
Win2K DNS server with a subdomain 18 characters or
longer, I can't ping the DNS name without getting
a "can't find" error from a PC on the same internal
network that is using the DNS of that server. But, from
outside on the Internet, I can ping without any problems.
Anyone have any ideas how to get around this problem?
Thanks.

The NetBIOS name is restricted to 15 bytes, whereas a Host name can be up to
63 bytes long. The whole FQDN can't be more than 255 characters and AD can
only accept 155 characters. Explained in the DNS Whitepapers and I assume
that applies to domain names, which honestly, I forget how long it can be,
but it's longer than 17 characters.
http://www.microsoft.com/windows2000/docs/w2kdns.doc

And see this about specifics of domain names:
http://www.microsoft.com/technet/tr...roddocs/entserver/sag_DNS_und_DomainNames.asp

This could be a CNAME issue. Are you using a CNAME? If so, see if these help
out:

281308 - Connecting to SMB Share on a Windows 2000-Based Server May Not Work
with an Alias Name [Doesn't work with CNAMES]:
http://support.microsoft.com/?id=281308

Also, it's highly suggested to keep the domain name the same as the NetBIOS
domain name (less than 15 characters) for interoperability and less
confusion.




--
Regards,
Ace

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This posting is provided "AS IS" with no warranties.

Ace Fekay, MCSE 2000, MCSE+I, MCSA, MCT, MVP
Microsoft Windows MVP - Active Directory