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Port 4011 (altserviceboot)

IANA assigns port 4011 to altserviceboot: Alternate Service Boot.

Registered (user) port, 1024-49151 TCPUDP

IANA assignment

Service nameProtoDescriptionAssigneeReference
altserviceboot TCP Alternate Service Boot Eric Dittert -
altserviceboot UDP Alternate Service Boot Eric Dittert -

Check what is listening on port 4011

Linux: is anything listening on TCP 4011?
sudo ss -tlnp 'sport = :4011'
Linux: UDP 4011
sudo ss -ulnp 'sport = :4011'
Linux / macOS: which process owns the port
sudo lsof -nP -i :4011
Older Linux / BSD (net-tools)
sudo netstat -tlnp | grep ':4011 '
Windows (Command Prompt)
netstat -ano | findstr :4011
Windows (PowerShell)
Get-NetTCPConnection -LocalPort 4011 -State Listen | Select LocalAddress,OwningProcess

Test it from outside

From another machine
nc -vz -w 5 HOST 4011
From Windows
Test-NetConnection HOST -Port 4011
UDP probe (no reply does not prove it is closed)
nc -vzu -w 5 HOST 4011

Block port 4011 in the firewall

ufw
sudo ufw deny 4011/tcp
iptables
sudo iptables -A INPUT -p tcp --dport 4011 -j DROP
nftables
sudo nft add rule inet filter input tcp dport 4011 drop
Windows Firewall
New-NetFirewallRule -DisplayName 'Block TCP 4011' -Direction Inbound -Protocol TCP -LocalPort 4011 -Action Block
ufw
sudo ufw deny 4011/udp
iptables
sudo iptables -A INPUT -p udp --dport 4011 -j DROP
nftables
sudo nft add rule inet filter input udp dport 4011 drop
Windows Firewall
New-NetFirewallRule -DisplayName 'Block UDP 4011' -Direction Inbound -Protocol UDP -LocalPort 4011 -Action Block

Related ports

4009chimera-hwm4010samsung-unidex4012pda-gate4013acl-manager

All port numbers · Open port checker
Assignment data: IANA port number registry (public domain), retrieved 2026-11-10.