Port 4335NETCONF Call Home over TLS

TCP 4335 is used by network devices to initiate TLS-protected NETCONF management sessions to a controller.

transport: tcp
in transit: encrypted
assignment: official
risk: 7/10
lookups: 0

also known as netconf-ch-tls, NETCONF over TLS Call Home

Technical Details

what runs on :4335

The device initiates a TCP connection to the manager on port 4335, then establishes TLS before exchanging NETCONF protocol messages. NETCONF hello messages negotiate capabilities, after which the peers exchange framed RPC requests and replies. This port is for NETCONF Call Home over TLS (RFC 8071); port 6513 is the conventional port for NETCONF over TLS without the Call Home assignment.

Security Information

exposure of :4335

risk score

7/ 10risk

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

remote access averages 3.8 across 204 ports — this one sits 3.2 above.

in transit

encrypted

payloads are protected on the wire

assignment

official

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

reachable over

tcp

every listening transport is another surface to filter at the edge

security overview

TLS protects the management session, but the service provides access to sensitive device configuration and operational data. Restrict the listener to expected device networks, validate peer certificates and identities, and keep NETCONF authorization narrowly scoped; it is not a general-purpose public service.

Record

iana registry entry

port: :4335
service: NETCONF Call Home over TLS
transport: TCP
encryption: tls / encrypted
assignment: iana registered
risk: 7/10risk
category: Remote Access Network Services
usage: A NETCONF-capable device initiates a connection to a management system for remote configuration and monitoring. This is the IETF-standard Call Home TLS port; it is uncommon in internet scans, and an open port may be a controller waiting for device connections.
lookups: 0rank 993
added: 2026-10-04
updated: 2026-10-04
references: IANA service name registry — port 4335
RFC 8071

Something wrong?

This record is maintained by the engineers who use port 4335. 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 2026-10-04.

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edit this record →back to the registry

Related Ports

all 204 in remote access →

the 8 most looked-up other ports in remote access — 204 ports carry that label.

port	service	proto	category	risk	views
:8000	Intel Remote Desktop / Alternate HTTP Port	TCP	Web Services	safe	84.3k
:8888	D2GS Admin Console	TCP	Remote Access	caution	83.7k
:8881	Atlasz Secure Server	TCP	Web Services	caution	67.6k
:5938	TeamViewer	TCPUDP	Remote Access	caution	65.0k
: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 :4335NETCONF Call Home over TLS

Technical Details

Security Information

Related Ports

Port 4335NETCONF Call Home over TLS