ORA-03135: connection lost contact

SQL*Plus: Release 10.2.0.1.0 – Production on Sun Sep 23 16:21:46 2012

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ERROR:
ORA-03135: connection lost contact

workaround:
On the Oracle database server machine open file $ORACLE_HOME/network/admin/sqlnet.ora
Set parameter
SQLNET.EXPIRE_TIME=XX

xx: number

enjoy
Osama Mustafa