Sensu-backend connecting out to us-west-2.compute.amazonaws.com

Sensu Go
1

Description of your problem

On a fresh install of sensu-backend, I see a TCP connection from sensu-backend out to an external IP address

root@sensu-backend:/home/ubuntu# lsof -i -n -P | grep sensu
sensu-bac 5529           sensu    7u  IPv4  53006      0t0  TCP 127.0.0.1:2380 (LISTEN)
sensu-bac 5529           sensu    8u  IPv4  53007      0t0  TCP 127.0.0.1:2379 (LISTEN)
sensu-bac 5529           sensu   12u  IPv4  53022      0t0  TCP 127.0.0.1:50562->127.0.0.1:2379 (ESTABLISHED)
sensu-bac 5529           sensu   14u  IPv4  53023      0t0  TCP 127.0.0.1:2379->127.0.0.1:50562 (ESTABLISHED)
sensu-bac 5529           sensu   15u  IPv4  53025      0t0  TCP 127.0.0.1:50564->127.0.0.1:2379 (ESTABLISHED)
sensu-bac 5529           sensu   16u  IPv4  53026      0t0  TCP 127.0.0.1:2379->127.0.0.1:50564 (ESTABLISHED)
sensu-bac 5529           sensu   18u  IPv6  53051      0t0  TCP *:8080 (LISTEN)
sensu-bac 5529           sensu   19u  IPv6  53053      0t0  TCP *:8081 (LISTEN)
sensu-bac 5529           sensu   20u  IPv6  53055      0t0  TCP *:3000 (LISTEN)
sensu-bac 5529           sensu   22u  IPv4  54433      0t0  TCP 10.3.3.27:51320->35.155.39.192:443 (ESTABLISHED)

The last connection to 35.155.39.192 looks suspicious, a reverse DNS lookup gives
ec2-35-155-39-192.us-west-2.compute.amazonaws.com

I searched the sensugo docs and googled it as best I could but couldn’t find anything, I looked in the logs - couldn’t see anything there.

Should I be worried? Is this normal? Can I stop it?

Environmental information

Operating system information

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Ubuntu 22.04

Package versions

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Sensu Go: 6.9.1+ee

Plugin information

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No plugins installed

2

Hey @madhatter22 :wave:

Your Sensu backend is connecting to Tessen, which is documented here:

Tessen is the Sensu call-home service. It is enabled by default on Sensu backends. Tessen sends anonymized data about Sensu instances to Sensu Inc., including the version, cluster size, number of events processed, and number of resources created (like checks and handlers). We rely on Tessen data to understand how Sensu is being used and make informed decisions about product improvements.

image
image803Ă—379 15.5 KB

This can be disabled as noted in the docs, but does provide good, anonymized, information for future product improvements

Best,

Justin

3

Hi Justin,

Thanks, that makes sense - I couldn’t find it in the docs when I searched but glad to know its expected behaviour.

Regards,
Grant.

1 Like
4

Hey Grant,

Glad to help. Also want to let you know, based on this conversation, I’ve requested an update to the docs to try and bring a bit more light to the dark where Tessen is concerned.

Best,

Justin