Port 8983 (Apache Solr)

Apache Solr search admin UI and API.

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

What port 8983 is used for

Apache Solr search admin UI and API.

Security: should port 8983 be open?

Do not expose to the internet. Exposed Solr instances were exploited via Velocity templates and DataImportHandler RCEs and Log4Shell. Keep internal and enable authentication.

IANA assignment

Port 8983 is in the registered range and has no IANA assignment. The usage above is unofficial but widespread.

Check what is listening on port 8983

Linux: is anything listening on TCP 8983?

sudo ss -tlnp 'sport = :8983'

Linux / macOS: which process owns the port

sudo lsof -nP -i :8983

Older Linux / BSD (net-tools)

sudo netstat -tlnp | grep ':8983 '

Windows (Command Prompt)

netstat -ano | findstr :8983

Windows (PowerShell)

Get-NetTCPConnection -LocalPort 8983 -State Listen | Select LocalAddress,OwningProcess

Test it from outside

From another machine

nc -vz -w 5 HOST 8983

From Windows

Test-NetConnection HOST -Port 8983

Block port 8983 in the firewall

ufw

sudo ufw deny 8983/tcp

iptables

sudo iptables -A INPUT -p tcp --dport 8983 -j DROP

nftables

sudo nft add rule inet filter input tcp dport 8983 drop

Windows Firewall

New-NetFirewallRule -DisplayName 'Block TCP 8983' -Direction Inbound -Protocol TCP -LocalPort 8983 -Action Block

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