[rabbitmq-discuss] clustering behind a firewall

[Kyle O'Donnell]

Hi,

I just moved one of my rabbit nodes into a firewalled network and am trying to figure out why the communication between the nodes is happening on ports that I haven't configured.  The cluster appears to be functioning normally now that I've opened all the appropriate ports, but still seeing ports used that I haven't defined. 

(ports 5672,4369 and range 58000-62000 are opened in both directions between all nodes)

Here is my config file:
[
  {kernel,
        [{inet_dist_listen_min, 58000},
        {inet_dist_listen_max, 62000}
        ]
  },
  {rabbit,
        [{cluster_nodes,                ['rabbit at node1', 'rabbit at node2', 'rabbit at node3','rabbit at node4', 'rabbit at node5', 'rabbit at node6', 'rabbit at node7', 'rabbit at node8']}
        ]
  }
].


Here is the traffic I am seeing on node2, watching for traffic from node1:

10:34:38.024623 IP node2.33420 > node1.4369: Flags [S], seq 1878005646, win 5840, options [mss 1460,nop,nop,sackOK,nop,wscale 10], length 0
10:34:38.025325 IP node1.4369 > node2.33420: Flags [S.], seq 2356457984, ack 1878005647, win 5840, options [mss 1380,nop,nop,sackOK,nop,wscale 10], length 0
10:34:38.025347 IP node2.33420 > node1.4369: Flags [.], ack 1, win 6, length 0
10:34:38.025414 IP node2.33420 > node1.4369: Flags [P.], seq 1:10, ack 1, win 6, length 9
10:34:38.026103 IP node1.4369 > node2.33420: Flags [.], ack 10, win 6, length 0
10:34:38.026254 IP node1.4369 > node2.33420: Flags [P.], seq 1:21, ack 10, win 6, length 20
10:34:38.026261 IP node2.33420 > node1.4369: Flags [.], ack 21, win 6, length 0
10:34:38.026279 IP node1.4369 > node2.33420: Flags [F.], seq 21, ack 10, win 6, length 010:34:38.026528 IP node2.33420 > node1.4369: Flags [F.], seq 10, ack 22, win 6, length 0
10:34:38.026622 IP node2.45073 > node1.58000: Flags [S], seq 1877745630, win 5840, options [mss 1460,nop,nop,sackOK,nop,wscale 10], length 0
10:34:38.026855 IP node1.4369 > node2.33420: Flags [.], ack 11, win 6, length 010:34:41.026136 IP node2.45073 > node1.58000: Flags [S], seq 1877745630, win 5840, options [mss 1460,nop,nop,sackOK,nop,wscale 10], length 0


I see the attempt on port 58000 (as specified), but I also see ports in the 30000 range.  I've restarted rabbit on both nodes and find that that the 30000 is a randomized port (I've seen it in the 30000,40000,50000, and 60000 range).

Is that normal?

Thanks,
Kyle