Port 20048NFS mount daemon

NFS mountd handles export discovery and mount requests for Unix and Linux NFS servers.

transport: tcp · udp
in transit: cleartext
assignment: official
risk: 7/10
lookups: 0

also known as rpc.mountd, NFS mount protocol

Technical Details

what runs on :20048

mountd implements the ONC RPC mount protocol, conventionally RPC program 100005, and normally listens on both TCP and UDP port 20048. Clients use it to query exported filesystems and obtain file handles for permitted exports; TCP uses ONC RPC record marking, while UDP carries individual RPC datagrams. Port 20048 is a common fixed assignment, although deployments can configure another port and clients may discover it through rpcbind on port 111.

Security Information

exposure of :20048

risk score

7/ 10risk

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

file transfer averages 4.0 across 129 ports — this one sits 3.0 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 mountd directly to the public internet. Attackers can query exports, probe NFS configuration, and attempt unauthorized mounts; weak export rules, AUTH_SYS identity spoofing, and legacy NFS deployments can turn exposure into access to sensitive files. Restrict it to trusted NFS clients with firewall rules, use strong export policies and root squashing, and use Kerberos/RPCSEC_GSS or a protected network where supported.

Record

iana registry entry

port: :20048
service: NFS mount daemon
transport: TCPUDP
encryption: cleartext
assignment: iana registered
risk: 7/10risk
category: File Transfer Network Services
usage: This port is used by rpc.mountd, the ONC RPC NFS mount protocol service, primarily with NFSv2 and NFSv3 servers. Engineers commonly encounter it alongside rpcbind on port 111 and NFS data service on port 2049; NFSv4 generally uses port 2049 directly and does not require mountd for ordinary mounts.
lookups: 0rank 994
added: 2026-08-25
updated: 2026-08-25
references: IANA service name registry — port 20048

Something wrong?

This record is maintained by the engineers who use port 20048. 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 2026-08-25.

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edit this record →back to the registry

Related Ports

all 129 in file transfer →

the 8 most looked-up other ports in file transfer — 129 ports carry that label.

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: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 :20048NFS mount daemon

Technical Details

Security Information

Related Ports

Port 20048NFS mount daemon