How is sorting work?

Any one knows how sorting works?

I am using postgresql 9.3 and runs on Linux machines.
I see different sorting order for the same set of return data.

On linux machines, databases are configured the same.
Database have encoding set to 'utf8' and locale='C'

query:
Select host_id, host_name from host_view order by host_id

hos_id (character varying 128)
host_name (character varying 255)

- On one linux machine (locate in U.S) , the query returned following:

host_id host_name
------------ ------------------
"00017486"; "lnx2.xx.yy.com"
"00017486"; "lnx1.xx.yy.com"

- On a different linux machine (locate in India), the query returned following:

host_id host_name
------------ ------------------
"00017486"; "lnx1.xx.yy.com"
"00017486"; "lnx2.xx.yy.com"

Thanks,
Quang.