# Elasticsearch nodes behaving strangely, timeouts, discovery, etc. (solution)

**URL:** <https://discuss.elastic.co/t/elasticsearch-nodes-behaving-strangely-timeouts-discovery-etc-solution/16302>\
**Category:** Elasticsearch\
**Created:** [March 11, 2014, 10:27pm UTC](https://discuss.elastic.co/t/elasticsearch-nodes-behaving-strangely-timeouts-discovery-etc-solution/16302 "2014-03-11T22:27:44Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![Robin\_Verlangen](https://sea2.discourse-cdn.com/elastic/user_avatar/discuss.elastic.co/robin_verlangen/32/1542_2.png) [@Robin\_Verlangen](https://discuss.elastic.co/u/Robin_Verlangen)\
**Post date:** [March 11, 2014, 10:27pm UTC](https://discuss.elastic.co/t/elasticsearch-nodes-behaving-strangely-timeouts-discovery-etc-solution/16302/1 "2014-03-11T22:27:44Z")

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Hi there,

In the past couple of months we have seen all sorts of strange behaviours  
from our ES nodes. Symptoms included:

- failed to detect master / nodes
- failed to connect to nodes
- all sorts of other zen discovery related issues, also with unicast enabled

Today we discovered that we had a couple of firewalls that we not just  
managing ports, but also messing with the connections. They included things  
like connection limits (fair enough for external traffic, but a killer for  
internal traffic), and system protections against a wide variety of things.

After disabling these protections and connection limits on our traffic  
everything seemed to jump back to normal instantly.

So make sure you check you have no hardware/software firewalls that are  
doing "smart" stuff. Even if you open the ports it might be possible that  
there is some kind of global "security policy".

Just to share with other people that might face the seem problems.

Best regards,

Robin Verlangen  
_Chief Data Architect_

W [http://www.robinverlangen.nl](http://www.robinverlangen.nl)  
E robin@us2.nl

[http://goo.gl/Lt7BC](http://goo.gl/Lt7BC)  
_What is CloudPelican? [http://goo.gl/HkB3D](http://goo.gl/HkB3D)_

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<div class="post-metadata">

**Author:** ![system](https://us1.discourse-cdn.com/elastic/original/3X/1/a/1ac57faf039f6b580b3f104ef42a2a89e41014de.png) [@system](https://discuss.elastic.co/u/system)\
**Post date:** [July 6, 2017, 1:44am UTC](https://discuss.elastic.co/t/elasticsearch-nodes-behaving-strangely-timeouts-discovery-etc-solution/16302/2 "2017-07-06T01:44:04Z")

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Closed on July 6, 2017, 1:44am UTC