Communication issues with hubs, robots, and probes

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Article ID: 127522

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Updated On:

Products

DX Infrastructure Management NIMSOFT PROBES

Issue/Introduction

probe throws a communication error. Error messages similar to the following are seen in the tunnel client and tunnel server logs:


hub: sockWrite Failed: 000000000725AD90 <hub IP address>/<port> 10054 (rc = -1, sfd = 6368, lenleft = 246)

Cause

- Unknown

Environment

UIM 8.51 (any release through 9.02)
hub 7.91 (any version through 7.97)

Resolution

It is possible that there is a firewall that is interrupting the communication between the tunnel client hubs and the tunnel server hub, or this issue may be due to network latency.


The keys to indicate that this might be a firewall issue are the "sockWrite Failed" message string and the lenleft value. Typically these are indicative of a firewall that shuts down the connection which it was still in use.


This typically occurs with firewalls that are "application aware".


The following is recommended for firewalls with application aware enabled:


The firewall rules put in place for UIM ports (48000-48050) should be:


Idle connection timeout: 7200

Max connection timeout: 7200

TCP Connection only : No application awareness (important)


Note: when application awareness is turned off the max connection & idle connection should be the same.