Port 287 (k-block)

IANA assigns port 287 to k-block: K-BLOCK.

Well-known (system) port, 0-1023 TCPUDP

IANA assignment

Service nameProtoDescriptionAssigneeReference

k-block TCP K-BLOCK Simon P Jackson -

k-block UDP K-BLOCK Simon P Jackson -

Linux: is anything listening on TCP 287?

sudo ss -tlnp 'sport = :287'

Linux: UDP 287

sudo ss -ulnp 'sport = :287'

Linux / macOS: which process owns the port

sudo lsof -nP -i :287

Older Linux / BSD (net-tools)

sudo netstat -tlnp | grep ':287 '

Windows (Command Prompt)

netstat -ano | findstr :287

Windows (PowerShell)

Get-NetTCPConnection -LocalPort 287 -State Listen | Select LocalAddress,OwningProcess

From another machine

nc -vz -w 5 HOST 287

From Windows

Test-NetConnection HOST -Port 287

UDP probe (no reply does not prove it is closed)

nc -vzu -w 5 HOST 287

ufw

sudo ufw deny 287/tcp

iptables

sudo iptables -A INPUT -p tcp --dport 287 -j DROP

nftables

sudo nft add rule inet filter input tcp dport 287 drop

Windows Firewall

New-NetFirewallRule -DisplayName 'Block TCP 287' -Direction Inbound -Protocol TCP -LocalPort 287 -Action Block

ufw

sudo ufw deny 287/udp

iptables

sudo iptables -A INPUT -p udp --dport 287 -j DROP

nftables

sudo nft add rule inet filter input udp dport 287 drop

Windows Firewall

New-NetFirewallRule -DisplayName 'Block UDP 287' -Direction Inbound -Protocol UDP -LocalPort 287 -Action Block

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