Iptables – Port suddenly closed. How to re-open

I've written a software module in PHP that manages the saving of data in different data stores (MySQL, ElasticSearch and Redis). To test the module, I've created several test plans in Apache JMeter, including some that make a lot of concurrent requests. The tests are run against a LAMP stack in an Ubuntu 14.04 LTS VM (a Vagrant box).

What I've observed is, that sometimes port 9200 (ElasticSearch) gets closed after a given number of requests. Which is fine, because I want to test scenarios where one of the data stores becomes unavailable. However, to validate the test results, I need that port open again.

ElasticSearch is still running and listening to the port.

Situation before test run

$ nmap -p 9200 localhost
(...)
PORT     STATE SERVICE
9200/tcp open  wap-wsp

$ sudo netstat -tlnp | grep '9200'
tcp6       0      0 :::9200                 :::*                    LISTEN      1057/java

Situation after test run

$ nmap -p 9200 localhost
(...)
PORT     STATE  SERVICE
9200/tcp closed wap-wsp

$ sudo netstat -tlnp | grep '9200'
tcp6       0      0 :::9200                 :::*                    LISTEN      1057/java

Question

So far, I've waited until the store opened up again or I've restarted the VM. However, this is very inconvenient, which leads me to the actual question:

Is there a command to re-open a closed port?

I've searched, but only found advise on how to configure iptables. I've tried

$ sudo iptables -A INPUT -d 0/0 -s 0/0 -p tcp --dport 9200 -j ACCEPT

But from what I gather, this only creates a rule, and it doesn't have any immediate effect on the port:

$ sudo iptables -L -n
Chain INPUT (policy ACCEPT)
target     prot opt source               destination         
ACCEPT     tcp  --  0.0.0.0/0            0.0.0.0/0            tcp dpt:9200

$ nmap -p 9200 localhost
(...)
PORT     STATE  SERVICE
9200/tcp closed wap-wsp