Port 4094Linux SysRq daemon

TCP 4094 is used by sysrqd to send Linux kernel SysRq commands remotely.

transport: tcp · udp
in transit: cleartext
assignment: official
risk: 8/10
lookups: 0

Technical Details

what runs on :4094

sysrqd is a Linux daemon that exposes kernel Magic SysRq actions over a text-based interactive TCP connection, normally on port 4094. A client authenticates with the configured password and can request SysRq commands; the available actions depend on kernel configuration. The IANA registration lists both TCP and UDP, but typical sysrqd deployments use TCP. The connection is not encrypted.

Security Information

exposure of :4094

risk score

8/ 10risk

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

remote access averages 3.7 across 199 ports — this one sits 4.3 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

SysRq commands can perform high-impact operations such as syncing disks, remounting filesystems, terminating processes, or rebooting the machine. Password authentication does not make an internet-facing service safe, particularly because the session is unencrypted; restrict access to trusted management networks or disable the daemon when it is not needed.

Record

iana registry entry

port: :4094
service: Linux SysRq daemon
transport: TCPUDP
encryption: cleartext
assignment: iana registered
risk: 8/10risk
category: Remote Access System
usage: On Linux systems running sysrqd, this port provides remote access to the kernel's Magic SysRq functions. The daemon is uncommon in internet-wide scans; the IANA assignment also lists UDP, but the usual sysrqd service uses TCP.
lookups: 0rank 993
added: 2026-10-03
updated: 2026-10-03
references: IANA service name registry — port 4094

Something wrong?

This record is maintained by the engineers who use port 4094. 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 2026-10-03.

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edit this record →back to the registry

Related Ports

all 199 in remote access →

the 8 most looked-up other ports in remote access — 199 ports carry that label.

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:8291	Winbox MikroTik Admin	TCP	Security	caution	62.9k
:8008	IBM HTTP Server Admin	TCP	Web Services	caution	58.3k
:135	Microsoft EPMAP	TCPUDP	Security	caution	51.9k
:23	Telnet	TCP	Remote Access	caution	34.8k

risk mix of the 8 listed

safe13%
caution88%

0 of 8 encrypted

Port :4094Linux SysRq daemon

Technical Details

Security Information

Related Ports

Port 4094Linux SysRq daemon