Port 8912Windows Home Server Client Backup

Legacy Windows Home Server systems use port 8912 for client-to-server backup traffic.

transport: tcp · udp
in transit: cleartext
assignment: official
risk: 5/10
lookups: 0

also known as wcbackup, Windows Client Backup

Technical Details

what runs on :8912

The IANA assignment is Windows Client Backup on TCP and UDP port 8912. In practice, the port is associated with Windows Home Server client backup exchanges; TCP is used for the client/server backup connection. The protocol is proprietary, and its handshake and message framing are not publicly documented as a general standard. This is a legacy, typically local-network service rather than a service expected on a public interface.

Security Information

exposure of :8912

risk score

5/ 10caution

worth attention. how exposed you are depends on configuration — don't leave it reachable from the internet without a reason.

file transfer averages 3.3 across 203 ports — this one sits 1.7 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 this legacy backup service directly to the internet. An reachable backup endpoint adds attack surface and may expose sensitive backup data or metadata; the protocol's security properties are not sufficiently documented to assume traffic is encrypted or safe to trust on an untrusted network. Restrict access to the trusted LAN and retire or isolate systems that no longer need it.

Record

iana registry entry

port: :8912
service: Windows Home Server Client Backup
transport: TCPUDP
encryption: cleartext
assignment: iana registered
risk: 5/10caution
category: File Transfer
usage: This port is associated with the Windows Home Server client backup service, used by client PCs to communicate with a home server for backups. It is mainly relevant on legacy Windows Home Server networks, not as a general-purpose Windows service.
lookups: 0rank 993
added: 2026-10-15
updated: 2026-10-15
references: IANA service name registry — port 8912

Something wrong?

This record is maintained by the engineers who use port 8912. 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 2026-10-15.

01edit any field on a page of its own
02a model checks it for accuracy and spam
03clean and confident goes live immediately

edit this record →back to the registry

Related Ports

all 203 in file transfer →

the 8 most looked-up other ports in file transfer — 203 ports carry that label.

port	service	proto	category	risk	views
:9080	Groove RPC	TCPUDP	Web Services	caution	70.8k
:17500	Dropbox LAN Sync	TCPUDP	File Transfer	caution	43.7k
:548	Apple Filing Protocol	TCP	File Transfer	caution	36.8k
:7000	Vuze HTTPS Tracker	TCPtls	Security	caution	28.9k
:1337	PowerFolder P2P	TCP	Security	caution	27.1k
:9001	SharePoint Authoring		Web Services	caution	26.3k
:8080	FilePhile Relay	UDP	File Transfer	caution	25.6k
:1337	WASTE Encrypted Sharing	TCP	Security	caution	22.9k

risk mix of the 8 listed

caution100%

1 of 8 encrypted

Port :8912Windows Home Server Client Backup

Technical Details

Security Information

Related Ports

Port 8912Windows Home Server Client Backup