Port 1099 (Java RMI registry)

Java RMI registry, often used for JMX remote management.

Registered (user) port, 1024-49151 TCP Development tools Do not expose to the internet

What port 1099 is used for

Java RMI registry, often used for JMX remote management.

Security: should port 1099 be open?

Do not expose to the internet. Unauthenticated RMI/JMX endpoints allow Java deserialization attacks and remote code execution. Keep internal and require JMX authentication with SSL.

IANA assignment

Service nameProtoDescriptionAssigneeReference

rmiregistry TCP RMI Registry Mark Hodapp -

rmiregistry UDP RMI Registry Mark Hodapp -

Check what is listening on port 1099

Linux: is anything listening on TCP 1099?

sudo ss -tlnp 'sport = :1099'

Linux / macOS: which process owns the port

sudo lsof -nP -i :1099

Older Linux / BSD (net-tools)

sudo netstat -tlnp | grep ':1099 '

Windows (Command Prompt)

netstat -ano | findstr :1099

Windows (PowerShell)

Get-NetTCPConnection -LocalPort 1099 -State Listen | Select LocalAddress,OwningProcess

Test it from outside

From another machine

nc -vz -w 5 HOST 1099

From Windows

Test-NetConnection HOST -Port 1099

Block port 1099 in the firewall

ufw

sudo ufw deny 1099/tcp

iptables

sudo iptables -A INPUT -p tcp --dport 1099 -j DROP

nftables

sudo nft add rule inet filter input tcp dport 1099 drop

Windows Firewall

New-NetFirewallRule -DisplayName 'Block TCP 1099' -Direction Inbound -Protocol TCP -LocalPort 1099 -Action Block

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Assignment data: IANA port number registry (public domain), retrieved 2026-11-10.