Port 4045NFS Network Lock Manager (lockd)

NFS lockd uses this port for RPC file-lock coordination; IANA lists it as Network Paging Protocol.

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

also known as npp, NLM

Technical Details

what runs on :4045

The commonly encountered service is the ONC RPC Network Lock Manager (NLM), RPC program 100021, rather than the IANA-listed Network Paging Protocol. NLM handles remote file-lock operations for NFSv2/v3 deployments over TCP or UDP; TCP carries ONC RPC using record marking, while UDP carries RPC datagrams. Solaris commonly pins lockd to port 4045, whereas other systems may register RPC services on ports discovered through rpcbind (port 111). NLM works alongside the Network Status Monitor (statd); NFSv4 uses integrated locking and normally does not need NLM.

Security Information

exposure of :4045

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 3.5 across 174 ports — this one sits 1.5 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 lockd to the public internet. It adds an RPC attack surface and can be targeted for denial of service or unwanted interference with NFS locking; restrict it to trusted NFS clients and networks, alongside the NFS and RPC services it depends on. RPC traffic is not encrypted by default, and NLM is not a substitute for access controls on NFS exports.

Record

iana registry entry

port: :4045
service: NFS Network Lock Manager (lockd)
transport: TCPUDP
encryption: cleartext
assignment: iana registered
risk: 5/10caution
category: File Transfer Network Services
usage: Although IANA assigns 4045 to Network Paging Protocol and reports unauthorized use, this port is commonly associated with the NFS Network Lock Manager, or lockd, especially on Solaris. It coordinates file locks for NFS clients and servers; NFSv4 generally handles locking within NFS itself.
lookups: 0rank 993
added: 2026-10-03
updated: 2026-10-03
references: IANA service name registry — port 4045

Something wrong?

This record is maintained by the engineers who use port 4045. 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 174 in file transfer →

the 8 most looked-up other ports in file transfer — 174 ports carry that label.

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risk mix of the 8 listed

caution100%

1 of 8 encrypted

Port :4045NFS Network Lock Manager (lockd)

Technical Details

Security Information

Related Ports

Port 4045NFS Network Lock Manager (lockd)