Hi All

I found a interesting  issue with /etc/hosts setting in different Linux system.

My stunnel.conf setting  like below

[HOST]

cert = client.crt

key = client.key

CAfile = server.crt

client = yes

accept = 10.160.160.88:57853

connect = 10.136.160.21:3520

I would like to connect server 10.136.160.21:3520  via stunnel  10.160.160.88:57853

Part A

If my hostname and  /etc/hosts setting in different System as followings all will works well

1. CentOS 7 32bit 

$hostname

localhost.localdomain

$ cat /etc/hosts  

127.0.0.1 localhost localhost4 localhost4.localdomain4

10.136.160.88 localhost.localadmin

2. Redhat 7 64bit

$hostname

localhost.localdomain

$ cat /etc/hosts  

127.0.0.1 localhost  localhost4 localhost4.localdomain4

10.136.160.88 localhost.localadmin

3. Ubuntu15.10 64bit

$hostname

virtual-machine

$ cat /etc/hosts  

127.0.0.1 localhost 

10.136.160.88 virtual-machine

Part B.

If the "127.0.0.1"  include the hostname in /etc/hosts, both CentOS and Fedora will fail,  but Ubuntu still work

1. CentOS 7 32bit 

$hostname

localhost.localdomain

$ cat /etc/hosts  

127.0.0.1 localhost localhost.localdomain localhost4 localhost4.localdomain4

10.136.160.253 localhost.localdomain

2. Redhat 7 64bit

$hostname

localhost.localdomain

$ cat /etc/hosts  

127.0.0.1 localhost localhost.localdomain localhost4 localhost4.localdomain4

10.136.160.88 localhost.localadmin

3. Ubuntu15.10 64bit

$hostname

virtual-machine

$ cat /etc/hosts  

127.0.0.1 localhost  virtual-machine

10.136.160.88 virtual-machine

I think it maybe not a stunnel issue, but I'd like to know why it has different behavior 

Thanks

Jay