how to verify opensuse's ident server is working ?

PostgreSQL docs say:

The “Identification Protocol” is described in RFC 1413. Virtually every Unix-like operating system ships with an ident server that listens on TCP port 113 by default. The basic functionality of an ident server is to answer questions like “What user initiated the connection that goes out of your port X and connects to my port Y?”.

i wanna know, how to verify opensuse’s ident server is working ? is there any out-of-the-box ident client ? is user name in response encrypted?
thanks advance, any suggestions is appreciated!

You can see which ports are listening usiing

netstat -tulpn

In my 12.2 system:

boven:~ # netstat -tulpn
Active Internet connections (only servers)
Proto Recv-Q Send-Q Local Address           Foreign Address         State       PID/Program name   
tcp        0      0 0.0.0.0:2049            0.0.0.0:*               LISTEN      -                   
tcp        0      0 0.0.0.0:44644           0.0.0.0:*               LISTEN      1603/rpc.mountd     
tcp        0      0 0.0.0.0:873             0.0.0.0:*               LISTEN      1373/xinetd         
tcp        0      0 0.0.0.0:3306            0.0.0.0:*               LISTEN      2050/mysqld         
tcp        0      0 0.0.0.0:111             0.0.0.0:*               LISTEN      1/init              
tcp        0      0 0.0.0.0:48400           0.0.0.0:*               LISTEN      -                   
tcp        0      0 0.0.0.0:37681           0.0.0.0:*               LISTEN      1603/rpc.mountd     
tcp        0      0 0.0.0.0:37139           0.0.0.0:*               LISTEN      1617/rpc.statd      
tcp        0      0 0.0.0.0:41235           0.0.0.0:*               LISTEN      1603/rpc.mountd     
tcp        0      0 0.0.0.0:21              0.0.0.0:*               LISTEN      1373/xinetd         
tcp        0      0 0.0.0.0:631             0.0.0.0:*               LISTEN      578/cupsd           
tcp        0      0 127.0.0.1:25            0.0.0.0:*               LISTEN      2242/master         
tcp        0      0 :::2049                 :::*                    LISTEN      -                   
tcp        0      0 :::54596                :::*                    LISTEN      1603/rpc.mountd     
tcp        0      0 :::42606                :::*                    LISTEN      1603/rpc.mountd     
tcp        0      0 :::111                  :::*                    LISTEN      1/init              
tcp        0      0 :::80                   :::*                    LISTEN      1682/httpd2-prefork 
tcp        0      0 :::59348                :::*                    LISTEN      1617/rpc.statd      
tcp        0      0 :::53815                :::*                    LISTEN      -                   
tcp        0      0 :::631                  :::*                    LISTEN      1/init              
tcp        0      0 ::1:25                  :::*                    LISTEN      2242/master         
tcp        0      0 :::41405                :::*                    LISTEN      1603/rpc.mountd     
udp        0      0 0.0.0.0:41187           0.0.0.0:*                           1603/rpc.mountd     
udp        0      0 0.0.0.0:760             0.0.0.0:*                           584/rpcbind         
udp        0      0 0.0.0.0:45355           0.0.0.0:*                           1603/rpc.mountd     
udp        0      0 0.0.0.0:45979           0.0.0.0:*                           1617/rpc.statd      
udp        0      0 127.0.0.1:945           0.0.0.0:*                           1617/rpc.statd      
udp        0      0 0.0.0.0:2049            0.0.0.0:*                           -                   
udp        0      0 0.0.0.0:55325           0.0.0.0:*                           -                   
udp        0      0 0.0.0.0:56416           0.0.0.0:*                           1603/rpc.mountd     
udp        0      0 0.0.0.0:111             0.0.0.0:*                           1/init              
udp        0      0 0.0.0.0:631             0.0.0.0:*                           1/init              
udp        0      0 10.0.0.154:123          0.0.0.0:*                           2105/ntpd           
udp        0      0 127.0.0.1:123           0.0.0.0:*                           2105/ntpd           
udp        0      0 0.0.0.0:123             0.0.0.0:*                           2105/ntpd           
udp        0      0 :::52426                :::*                                1603/rpc.mountd     
udp        0      0 :::760                  :::*                                584/rpcbind         
udp        0      0 :::60784                :::*                                -                   
udp        0      0 :::2049                 :::*                                -                   
udp        0      0 :::33833                :::*                                1617/rpc.statd      
udp        0      0 :::38998                :::*                                1603/rpc.mountd     
udp        0      0 :::111                  :::*                                1/init              
udp        0      0 2001:980:91a0:1:21b:123 :::*                                2105/ntpd           
udp        0      0 2001:980:91a0:1:b10:123 :::*                                2105/ntpd           
udp        0      0 ::1:123                 :::*                                2105/ntpd           
udp        0      0 fe80::21b:fcff:fe7f:123 :::*                                2105/ntpd           
udp        0      0 :::123                  :::*                                2105/ntpd           
udp        0      0 :::53895                :::*                                1603/rpc.mountd     
boven:~ # 

There is no port 113 there, which is confirmed with

boven:~ # netstat -tulpn | grep 113
boven:~ # 

Thus there isn’t a server serving on port 113. Would a bit of a security hole if it was running by default IMHO.

But I find using YaST > Software > Software Management the following package on the 12.2 OSS repo (not installed):

oidentd - Configurable IDENT Server That Supports NAT/IP Masquerading

Oidentd is an ident (rfc1413 compliant) daemon that runs on Linux, Darwin, FreeBSD, OpenBSD, NetBSD, and Solaris. oidentd can handle IP masqueraded/NAT connections on Linux, Darwin, FreeBSD (ipf only), OpenBSD, and NetBSD. Oidentd has a flexible mechanism for specifying ident responses. Users can be granted permission to specify their own ident responses. Responses can be specified according to host and port pairs.

Maybe that is what you are after.

thanks man, your reply helps me a lot.
i installed oidentd, modified Oidentd startup options(so it will listen for IPv6), then started it, and it works well with postgresql ident authentications!
by the way, pidentd is out-of-the-box, without none modifications.

Nice you got what you wanted. Enjoy!