Friday, 22 April 2011

Io Error: Got minus one from a read call

When trying to connect using oracle sqldeveloper this error messages is thrown. I came across this error two times, on each occasion different cause.

1)  Make sure you are connecting to the correct port, wrong port also gives the error above.

2) This is happening becuase oracle is using ACL (access control list) where only authorised clients are given access.

check sqlnet.ora file ($ORACLE_HOME/network/admin)

tcp.validnode_checking = yes

we can either disable this checking

tcp.validnode_checking = no

or add the node in the acl.


bounce the listener and try connecting again

if oracle apps is using use addlnctl script to bounce it.


  1. This comment has been removed by the author.

  2. good advice
    although, in my case i just simply didnt connect to correct port
    by some reason used the 8080 port not 1521, because when opening the database app, it tried to open addess.

    good luck and thanks!

    1. I came across the one you mentioned also today. Thank you very much.

      Keep sharing :)

  3. Its Helped me as well...thanks very much

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