From: "Darryl L. Pierce" <mcpierce@...>
Date: 2011-08-27T02:16:33+09:00
Subject: Re: ssh login to a host

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On Sat, Aug 27, 2011 at 02:03:12AM +0900, Dan Nachbar wrote:
>=20
> On Aug 26, 2011, at 11:59 AM, Rick Tan wrote:
>=20
> > Hi,
> >=20
> > Can someone give me some advice on how to reliably check that a server
> > is alive and accepts ssh login?  Have tried ping but that opens a small
> > window that ssh login is still not available.
>=20
> With 1.9.2 you can say -
>=20
> require 'socket'
> s =3D TCPSocket.open('myfavoritehost.com', 22)
>=20
> s.gets(3).eql? "SSH"

Using the following in IRB:

irb(main):008:0> s =3D TCPSocket.open('localhost', 22)
=3D> #<TCPSocket:0x7f5f1cb95ff0>
irb(main):009:0> s.gets.eql? "SSH"
=3D> false

Retrying with s.gets(3).eql? "SSH" theres:

irb(main):011:0> s.gets(3).eql? "SSH"
TypeError: can't convert Fixnum into String
	from (irb):11:in `gets'
	from (irb):11
	from :0

Instead try:

s.gets.include? "SSH"

though I'd suspect that an established connection on port 22 should be
sufficient to say it's enabled and working, and just use the response to
check what versions (SSH1 or SSH2) are supported.

--=20
Darryl L. Pierce <mcpierce@gmail.com>
http://mcpierce.multiply.com/
"What do you care what people think, Mr. Feynman?"

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