hostname restrictions

[David McMullen_1]

Is there a restriction that hostnames must start with an alpha character? I was told that a hostname could not start with a number (0-9). I am I being told a tall tale?

[Trevor Dyson · Accepted solution]

This is correct - hostnames must start with a letter not a number and be a maximum of 8 characters. A combination of numbers and letters can be used for the rest. Underscores are accepted but should not be used as some DNS servers may have a problem with that.

Cheers, Trevor

[Dan Hetzel]

Hi David,

You're right ! Names must start with a letter.
The name length shouldn't exceed 8 characters to remain compatible with some old stuff, even is the maximum is defined as 64 in file sys/param.h (MAXHOSTNAMELEN).

As Trevor told you, some DNS don't like the underscore character, so you'd better avoid it.


Best regards,

Dan

[Paula J Frazer-Campbell]

Hi
If you wish to use a number then spell it, i.e.

one-sys
two-sys

Paula

[Dan Hetzel]

Hi Paula,

One of my clients in France named the systems the following way:
GHT1HP
GHT2HP
GHT3HP....
Which, spelled in french sounds like:
"J'ai achete un HP", 'J'ai achete deux HP"...
meaning
"I bought one HP", "I bought two HP"....

Stupid, isn't it?

Dan

[Paula J Frazer-Campbell]

Hi Dan
Talking of silly server names our sister company Cosmos has two NT servers called Hotpoint and Zanussi because the boxes look like washing machines.

;-)

Paula

[nnf97]

To each his/her own :)
We have sys15, sys30.
And then we have, Fred, Wilma, Barney and Louise.
I visited a client yesterday and the oldest server, ready for the mortuary is appropriately named Morticia. :)

Have Fun,
Nabeel

[Rita C Workman]

Yes the standard is maximum 8,
must start with a letter and is recommended that you include a number (although not required).

Just so you have something additional:
It is suggested (note suggested..) you not include underscores BUT you should not use metacharacters (like @ / " : etc) as part of the hostname.

/rcw

[David McMullen_1]

Thanks for all the reponses. And the laughs. Now can anyone tell me why this is?

TIA

davidmac

[Trevor Dyson]

Generally for backward compatibility with older network client, server and utility software. The 8 char/no start with number/alphanumeric only rule is the lowest common denominator that will work with all network software that uses the hostname in some way.

You could configures your hostname as "123@^%%%55andahalf" however, maybe not today, maybe not tommorow but some day and soon, something will barf.