Port 49152 Dynamic / ephemeral range starts · TCP and UDP

What runs on port 49152

The start of the IANA dynamic/private (ephemeral) port range, 49152–65535: the ports a client is given for the outgoing side of a connection, and the range Windows uses for RPC dynamic endpoints. Linux defaults to 32768–60999 instead (net.ipv4.ip_local_port_range), which matters when you run out of ports on a busy proxy or NAT. Specific services also live here by convention: 49152 is the default for Supermicro IPMI's web UI, UPnP on some devices, and the start of Windows' RPC range.

Software that uses it: Every TCP/IP stack (client side) · Windows RPC dynamic endpoints · Supermicro IPMI (web, some firmware) · UPnP device descriptions

Should port 49152 be open?

Private network or VPN only. Nothing good comes from this port being reachable from the internet. Keep it on an internal network, reach it over a VPN or an SSH tunnel, and firewall it from everything that does not need it.

• "Cannot assign requested address" on a busy client is port exhaustion: raise ip_local_port_range, lower tcp_fin_timeout, or use more source addresses.
• Windows firewall rules for WMI/RPC need this whole range, or a fixed port configured on the service.

Check port 49152

# on the host: is anything listening, and which process?
ss -ltnp 'sport = :49152'
ss -lunp 'sport = :49152'
sudo lsof -i :49152

# from another machine: is it reachable?
nc -zv host 49152
nmap -p 49152 host
nc -zuv host 49152
sudo nmap -sU -p 49152 host
curl -v telnet://host:49152      # raw TCP connect test, Ctrl-C to leave

A port that answers from the internet when it should not is the finding; nmap from a machine outside your network (or a VPS) is the honest test, because scans from inside the LAN pass the firewall you are trying to verify.

Allow or block port 49152

# ufw (Ubuntu/Debian)
sudo ufw allow from 10.0.0.0/8 to any port 49152 proto tcp
sudo ufw allow from 10.0.0.0/8 to any port 49152 proto udp
sudo ufw deny 49152/tcp
sudo ufw deny 49152/udp

# nftables
nft add rule inet filter input ip saddr 10.0.0.0/8 meta l4proto { tcp, udp } th dport 49152 accept
nft add rule inet filter input meta l4proto { tcp, udp } th dport 49152 drop

# iptables (legacy)
iptables -A INPUT -p tcp --dport 49152 -s 10.0.0.0/8 -j ACCEPT
iptables -A INPUT -p tcp --dport 49152 -j DROP
iptables -A INPUT -p udp --dport 49152 -s 10.0.0.0/8 -j ACCEPT
iptables -A INPUT -p udp --dport 49152 -j DROP

# firewalld
sudo firewall-cmd --permanent --add-rich-rule='rule family=ipv4 source address=10.0.0.0/8 port port=49152 protocol=tcp accept'

Replace 10.0.0.0/8 with the networks that need access. Allowing by source address is the rule that matters; "allow 49152" with no source is just "open".

Related ports

• 135 MS RPC — Windows RPC endpoint mapper
• 65535 Highest port — End of the ephemeral range

Part of the port number reference. Ports are 16-bit numbers; see also the subnet calculator and the packet decoder, which shows ports inside TCP and UDP headers.

Questions