How do I change SSLCIPH on a channel?

Regular readers of my blog know that most of the topics I write on appear simple, but have hidden depth, this topic is no exception.

The simple answer is

  • For the client ALTER CHL(xxxx) CHLTYPE(CLNTCONN) SSLCIPH(new value)
  • For the svrconn
    • ALTER CHL(xxxx) CHLTYPE(SVRCONN) SSLCIPH(new value)
    • REFRESH SECURITY

The complexity occurs when you have many clients trying to use to the channel, and you cannot change them all at the same time (imagine trying to change 1000 of them – when half of them are not under your control). For the clients that have not changed, you will get message

AMQ9631E: The CipherSpec negotiated during the SSL handshake does not match the required CipherSpec for channel ‘…’.

in the /qmgrs/xxxx/errors/AMQERR01.LOG

For this problem the CCDT is your friend. See my blog post here.

I have a client channel CHANNEL(C1) CHLTYPE(CLNTCONN)

On my CCDT queue manager I created another channel the same as the one I want to update.

DEF CHANNEL(C2) CHLTYPE(CLNTCONN) LIKE(C1)

On my server queue manager I used

DEF CHANNEL(C2) CHLTYPE(SVRCONN) LIKE(C1)

DEFINE CHLAUTH(C2) TYPE(BLOCKUSER)
USERLIST(….)

REFRESH SECURITY

When I ran my sample connect program, it connected using C1 as before.

On the MQ Server, I changed the SSLCIPH to the new value for C1.

When I ran my sample connect program it connected using channel(C2). In the AMQERR01.LOG I had the message

AMQ9631E: The CipherSpec negotiated during the SSL handshake does not match the required CipherSpec for channel ‘C1′

So the changed channel did not connect, but the second channel with the old cipher spec worked succesfully. (The use of the backup channel was transparent to the application)

I then changed DEF CHANNEL(C1) CHLTYPE(CLNTCONN) so SSLCIPH had the correct, matching value. When my sample program was run, it connected using channel C1 as expected.

Once I have changed all my channels, and get no errors in the error log.

  • I can change the CHLAUTH(C2) BLOCKUSER(*) and either set warning, or give no warning and no access
  • Remove C2 from the CCDT queue manager, so applications no longer get this in their CCDT
  • Finally delete the channel C2 on the server.
  • Go down the pub to celebrate a successful upgrade!


2 thoughts on “How do I change SSLCIPH on a channel?

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