/etc/hosts - how does that file work?? - was weird nfs issues.

[Peter]

> On Thursday 04 June 2009 20:48:21 Peter wrote:
>> iH,
>>   This all started with NFS not mounting at boot....so, testing in VMs:
>
> <snip>
>
>> Why is ping using one IP, and ssh/mount_nfs/showmount using another IP
from /etc/hosts?
>
> Q: Where is described that name resolution for A or PTR records should
be
> returned in a fixed order and that a consumer should always use the
first
> one
> returned?
> A: Nowhere. Name servers are encouraged to do round-robin returns if not
specified otherwise. Applications may sort/pick at their own leisure.
>
> --
> Mel

I do not think /etc/hosts does round robin, I always assumed first match
wins...DNS/bind I would understand...

Why does ping always return the 172.20.6.1 address,
 and ftp,nc,ssh,telnet,fetch _always_ uses the 116 address?

I would assume at least sometimes it would hit the 172 address with
anything besides ping - but it only ping hits the 172 address...
If so, I'd guess there would be consistency between ping lookups and
'telnet/ssh/etc' lookups...

Why if the 116.23.45.3 last octet is bumped up, everything _always_
returns the 172 address?

client# grep server /etc/hosts
172.20.6.1              server.test server
116.23.45.5             server.test server
client# telnet server
Trying 172.20.6.1...
telnet: connect to address 172.20.6.1: Connection refused
Trying 116.23.45.5...

/etc/hosts - 'server' changed to
116.23.45.3:

client# telnet server
Trying 116.23.45.3...
telnet: connect to address 116.23.45.3: Operation timed out
Trying 172.20.6.1...
telnet: connect to address 172.20.6.1: Connection refused
telnet: Unable to connect to remote host

if server has ip>116.23.45.3, it always uses the 172 address first...

but ping always uses the  172...
even if third entry is added into /etc/hosts - nothing ever uses it as the
first/primary IP.

Is there an algorithm based on IP/program being used and the returned IP?