Setting FQDN hostname and dot

Question

I was wondering if I am editing a file such as /etc/hosts or /etc/sysconfig/network should I put a . at the end of the name. such as test.example.com.

Is there a difference? Would anything break either way.

score 6 · Answer 1 · answered Nov 30 '11 at 10:54

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According to man hosts:

Host names may contain only alphanumeric characters, minus signs ("-"), and periods ("."). They must begin with an alphabetic character and end with an alphanumeric character.

answered Nov 30 '11 at 10:54

dunxd

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score 2 · Answer 2 · answered Nov 30 '11 at 11:51

Entries in /etc/hosts are never expanded with a domain, it's a simple table lookup, and hence, trailing dots are meaningless and likely to cause issues. Also as mentioned in another answer, the specification for /etc/hosts rules them out (for this reason).

score 2 · Answer 3 · answered Mar 21 '12 at 08:51

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Trailing dot is not meaningless. If you try to access a host with FQDN(which includes trailing dot), your application will lookup the name from DNS not /etc/hosts if the hostname in /etc/hosts does not have trailing dot.

answered Mar 21 '12 at 08:51

Minsuk Song

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score 1 · Answer 4 · answered Nov 30 '11 at 08:33

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I have never seen anyone use a trailing dot there, so you probably shouldn't. Even though nothing might break right now, it's just tempting fate, as something might not expect it.

answered Nov 30 '11 at 08:33

Teddy

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Setting FQDN hostname and dot

4 Answers4