Port / TCP
5601Kibana
Kibana's web interface for querying and visualising Elasticsearch indices.
If it is internet-facing: Finding 5601 open to the internet is a finding in its own right — it warrants an explanation, not just a rule.
Exposure
Behind a gateway
Transport
Encryption optional
Risk if public
High
Exposure verdict
Port 5601 should sit behind a reverse proxy, VPN, or source allow-list rather than being forwarded at the perimeter. Publishing it directly puts an administrative or internal interface on the open internet.
Encryption is available but negotiated or configured rather than guaranteed. A client that does not insist on it will silently fall back to plaintext.
Registered with IANA on request, but bindable by any unprivileged user. Registration records intent — it does not reserve the port, so collisions between products are common.
Grouped with the other containers & platform ports so a rule written for one can be checked against its neighbours.
What actually goes wrong
2 notes- Kibana is a full read interface to whatever the cluster holds — logs, and often the personal data inside them.
- Older self-managed deployments shipped without authentication entirely; confirm security is enabled, not assumed.
Recommended firewall rule
Allow only from 10.0.0.0/8, drop the rest
Swap in the CIDR your administrators or application tier actually come from — the point is that the default answer is no.
ufw
sudo ufw allow from 10.0.0.0/8 to any port 5601 proto tcpiptables
sudo iptables -A INPUT -p tcp -s 10.0.0.0/8 --dport 5601 -j ACCEPT
sudo iptables -A INPUT -p tcp --dport 5601 -j DROPIf you do need it open to everyone
sudo ufw allow 5601/tcpWrite down why. An unexplained allow rule outlives the person who added it, and the next reviewer has no way to tell a deliberate exception from an accident.
Check what is really there
Listening locally
sudo ss -tlpn 'sport = :5601'The bind address is the answer that matters: 127.0.0.1 is local-only, 0.0.0.0 and :: mean every interface.
Listening (macOS)
sudo lsof -nP -iTCP:5601 -sTCP:LISTENmacOS ships lsof rather than ss; this names the owning process and user.
From outside
nmap -sV -Pn -p 5601 <host>A version probe confirms whether Kibana is actually what answers, rather than trusting the number. Only scan hosts you are authorised to test.
Reachability
nc -vz <host> 5601The quick yes/no when you only need to know whether a path exists through the firewall.