Try below code against not-opened (or blocked on firewall) port:

from time import sleep
from proton.utils import BlockingConnection

conn = None

while True:
  print "============================================================================================"
  sleep(0.1)
  try:
    conn = BlockingConnection("proton+amqp://example.com:12345", ssl_domain=None, heartbeat=10)
  except Exception, e:
    print e

Monitor RSS usage and opened FDs.

Current behaviour:

• RSS usage grows (until the FDs get deplenished due to ulimit)
• FDs grow (until deplenished) - due to pipes opened

I think (at least testing something similar on old 0.9 release) this is due to removal of pni_timer_finalize method in:

https://github.com/apache/qpid-proton/commit/8c6c7c53198f4152472572b8fccc5ab453d9ca86#diff-1263a41bd7a5218b033cc33321977fb9L444

(L444 - L462). So I expect current upstream is affected the same (dont have bandwidth to check it there).