port number changes in listener.log

Hi,

on 10.2.0.3

In my listener.ora I have given port 1521.

In tnsnames.ora also 1521.

When I try to connect to my db on the dbserver,  I receive :

sqlplus system@MYDB

ORA-12514: TNS:listener does not currently know of service requested.

 

in listener.log I have

07-NOV. -2013 09:04:54 * (CONNECT_DATA=(SERVICE_NAME=MYDB)(CID=(PROGRAM=D:\oracle\bin\sqlplus.exe)(HOST=SERVER)(USER=user))) * (ADDRESS=(PROTOCOL=tcp)(HOST=127.0.0.1)(PORT=4358))

 

or

(ADDRESS=(PROTOCOL=tcp)(HOST=127.0.0.1)(PORT=1858))

or

(ADDRESS=(PROTOCOL=tcp)(HOST=127.0.0.1)(PORT=1869))

 

In sqlnet.log I have

TNS-12564: TNS : connetion refused

 

My question is why in listener.log I have different port numbers instead of 1521 ?