How can I be confirm that data is encrypted over the network using SSL

I have configured SSL connection between client/server using self-signed certificate.

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SSL connection (cipher: DHE-RSA-AES256-SHA, bits: 256)

postgres=# \l
        List of databases
   Name    |  Owner   | Encoding
-----------+----------+----------
 postgres  | postgres | UTF8
 template0 | postgres | UTF8
 template1 | postgres | UTF8
(3 rows)
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PGDATA dir:

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-bash-3.2$ ls -l
total 84
drwx------ 5 postgres postgres  4096 May  4 14:09 base
drwx------ 2 postgres postgres  4096 May  5 10:58 global
...
-rw------- 1 postgres postgres  3600 May  4 14:17 server.crt
-rw------- 1 postgres postgres   887 May  4 14:17 server.key
-rw------- 1 postgres postgres  2195 May  4 14:16 server.req

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Client ~/.postgresql dir

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-bash-3.2$ ls -l
total 12
-rw-r--r-- 1 postgres postgres 3259 May  4 18:36 postgresql.crt
-rw------- 1 postgres postgres  887 May  4 18:35 postgresql.key
-rw-r--r-- 1 postgres postgres 2080 May  4 18:35 postgresql.req

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I set the $PGSSLMODE=require to encrypt data across the netwrok.


How could I be sure that data is encrypted over the network?