See https://issues.apache.org/jira/browse/QPID-1819
Fixed on qpid trunk by r780719. (Workaround until that is available through new MRG packages is to reduce the max-frame-size option in ConnectionSettings). To test, send large messages (e.g. using perftest) with the cyrus-sasl-md5 package installed and use the DIGEST-MD5 mechanism if available (it is usually preferred over other mechanisms, but can be forced by specifying the mechanism on command line).
Tested: on 752581-26 bug aapears (but only on x86_64) on later it does not, tested on 946106-11 it is fixed validated on RHEL5.5/RHEL4 i386 / x86_64 packages: # rpm -qa | grep -E '(qpid|openais|rhm)' | sort -u openais-0.80.6-16.el5_5.2 openais-devel-0.80.6-16.el5_5.2 python-qpid-0.7.946106-11.el5 qpid-cpp-client-0.7.946106-11.el5 qpid-cpp-client-devel-0.7.946106-11.el5 qpid-cpp-client-devel-docs-0.7.946106-11.el5 qpid-cpp-client-ssl-0.7.946106-11.el5 qpid-cpp-mrg-debuginfo-0.7.946106-8.el5 qpid-cpp-server-0.7.946106-11.el5 qpid-cpp-server-cluster-0.7.946106-11.el5 qpid-cpp-server-devel-0.7.946106-11.el5 qpid-cpp-server-ssl-0.7.946106-11.el5 qpid-cpp-server-store-0.7.946106-11.el5 qpid-cpp-server-xml-0.7.946106-11.el5 qpid-java-client-0.7.946106-7.el5 qpid-java-common-0.7.946106-7.el5 qpid-tools-0.7.946106-8.el5 rhm-docs-0.7.946106-4.el5 rh-tests-distribution-MRG-Messaging-qpid_common-1.6-52 ->VERIFIED
Technical note added. If any revisions are required, please edit the "Technical Notes" field accordingly. All revisions will be proofread by the Engineering Content Services team. New Contents: A client no longer stops responding when a large message is sent and the Digest-MD5 mechanism with a security layer is in use.