Cant run two separate versions of Elasticsearch on the same machine

I am trying to run two separate versions of Elasticsearch as follows

version 1.7.2 elastic172
http.port: 9200
transport.tcp.port: 9301


version 2.3.5 elastic235
http.port: 9201
transport.tcp.port: 9300

i keep rest of the settings as default. Version 1.7.2 starts up just fine and i can test it using curl

Version 2.3.5 starts up as well, however it runs into some exception like

    [2016-08-25 13:33:23,596][WARN ][bootstrap                ] unable to install syscall filter: seccomp unavailable: CONFIG_SECCOMP not compiled into kernel, CONFIG_SECCOMP and CONFIG_SECCOMP_FILTER are needed
[2016-08-25 13:33:23,760][INFO ][node                     ] [Neuronne] version[2.3.5], pid[28287], build[90f439f/2016-07-27T10:36:52Z]
[2016-08-25 13:33:23,760][INFO ][node                     ] [Neuronne] initializing ...
[2016-08-25 13:33:24,318][INFO ][plugins                  ] [Neuronne] modules [reindex, lang-expression, lang-groovy], plugins [], sites []
[2016-08-25 13:33:24,340][INFO ][env                      ] [Neuronne] using [1] data paths, mounts [[/home (bluej670:/newhome/home)]], net usable_space [1.1tb], net total_space [3.6tb], spins? [possibly], types [nfs]
[2016-08-25 13:33:24,341][INFO ][env                      ] [Neuronne] heap size [989.8mb], compressed ordinary object pointers [true]
[2016-08-25 13:33:24,341][WARN ][env                      ] [Neuronne] max file descriptors [8192] for elasticsearch process likely too low, consider increasing to at least [65536]
[2016-08-25 13:33:25,767][INFO ][node                     ] [Neuronne] initialized
[2016-08-25 13:33:25,767][INFO ][node                     ] [Neuronne] starting ...
[2016-08-25 13:33:25,827][INFO ][transport                ] [Neuronne] publish_address {}, bound_addresses {[::1]:9300}, {}
[2016-08-25 13:33:25,831][INFO ][discovery                ] [Neuronne] elastic235/F3LQQNenSIKsm8zocG2muQ
[2016-08-25 13:33:25,958][WARN ][transport.netty          ] [Neuronne] exception caught on transport layer [[id: 0x68b84cce, / => /]], closing connection
    at org.elasticsearch.transport.netty.MessageChannelHandler.handleException(

and then it goes on for while and at the end i see

[2016-08-25 13:33:30,358][INFO ][cluster.service          ] [Neuronne] new_master {Neuronne}{F3LQQNenSIKsm8zocG2muQ}{}{}, reason: zen-disco-join(elected_as_master, [0] joins received)
[2016-08-25 13:33:30,381][INFO ][http                     ] [Neuronne] publish_address {}, bound_addresses {[::1]:9201}, {}
[2016-08-25 13:33:30,381][INFO ][node                     ] [Neuronne] started
[2016-08-25 13:33:30,394][INFO ][gateway                  ] [Neuronne] recovered [0] indices into cluster_state

but here is the result if i curl it

curl <myHostName>:9201
curl: (7) couldn't connect to host

am i missing something in either yml?

Does <myHostName> resolve to Because per the above log, that is what ES is listening on.

I would make 1.7 settings more restrictive.

Disable multicast
Change unicast list of nodes to only