[rabbitmq-discuss] AMQP protocol version mismatch

Wed Aug 29 14:56:25 BST 2012

On 08/29/2012 02:11 PM, Paolo wrote:
> Thanks for your prompt response.
> Maybe i explained wrong,

I suspect it was my answer that was not clear enough...

> the RabbitMQ server works fine: I can also use
> the plugin rabbitmq_management and view all active queues.
> My problem is different, my application uses a library AMQP-client.jar
> to communicate with the server rabbit (AMQP-client-2.7.1.jar or
> AMQP-client-2.8.6.jar depending on the version of server).
> Using this library trying to connect to the serverrabbit, iget the error
> "*com.rabbitmq.client.MalformedFrameException: AMQP protocol version
> mismatch* *, we are version 0-9-1, server sent signature 1,1,0,10**. *"
> It seems that the client is incompatible with the server

Right, and I suspect (I could of course be wrong!) that it is not 
actually RabbitMQ your client is connecting to but a Qpid server (qpidd, 
which supports version 0-10 as identified by the rejected protocol 
header above).

Perhaps RabbitMQ was unable to listen on 5672 because it was already in 
use by Qpid (because the qpidd service is enabled by default on Centos). 
I'm not familiar enough with the management plugin to say for sure, but 
I suspect that is communicating with the RabbitMQ server over HTTP or 
some port other than 5672. You may see some errors in the RabbitMQ logs 
however.

Try running /sbin/service qpidd status, if that shows something running, 
try /sbin/service qpidd stop and then restart RabbitMQ and try your 
client application again.