Port 3493Network UPS Tools (NUT)

NUT uses this port for network monitoring and control of uninterruptible power supplies.

transport: tcp · udp
in transit: cleartext
assignment: official
risk: 6/10
lookups: 0

also known as nut, upsd, NUT protocol

Technical Details

what runs on :3493

NUT normally uses TCP port 3493 for a line-oriented client/server protocol. Clients connect to upsd, exchange commands and responses to list UPS devices, retrieve variables, authenticate, and issue permitted actions; UPS instances are addressed by configured names. UDP 3493 is registered but is not the usual transport for standard NUT client/server operation. Traffic is cleartext by default, although deployments can use TLS-capable configurations or an external secure tunnel.

Security Information

exposure of :3493

risk score

6/ 10risk

treat as sensitive. widely scanned and regularly exploited when reachable — restrict it to known sources.

network services averages 2.9 across 1,025 ports — this one sits 3.1 above.

in transit

cleartext

credentials and payloads are readable by anyone on path

assignment

official

registered with iana for this service — scanners fingerprint it by number

reachable over

tcp · udp

udp is connectionless — source addresses are trivially spoofed and it is a reflection favourite

security overview

Do not expose NUT directly to the public internet. An exposed service may disclose UPS, battery, and power-state information, while authenticated users with control privileges can issue actions such as shutdown or outlet control; cleartext deployments can also expose credentials and commands to network observers. Restrict access with firewall rules or VPNs, use least-privilege NUT accounts, and keep the implementation updated.

Record

iana registry entry

port: :3493
service: Network UPS Tools (NUT)
transport: TCPUDP
encryption: cleartext
assignment: iana registered
risk: 6/10risk
category: Network Services System
usage: NUT's `upsd` server listens here for clients such as `upsmon`, `upsc`, and `upscmd` to monitor UPS status and perform authorized control operations. Engineers typically encounter it on a UPS management host, with the UPS itself connected by USB, serial, SNMP, or another backend.
lookups: 0rank 994
added: 2026-09-08
updated: 2026-09-08
references: IANA service name registry — port 3493
RFC 9271

Something wrong?

This record is maintained by the engineers who use port 3493. Every field on it is editable — change what's wrong, say how you know, and a reviewer publishes it, usually within a minute. Last touched 2026-09-08.

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all 1,025 in network services →

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risk mix of the 8 listed

caution100%

0 of 8 encrypted

Port :3493Network UPS Tools (NUT)

Technical Details

Security Information

Related Ports

Port 3493Network UPS Tools (NUT)