Port 4190 (sieve)

IANA assigns port 4190 to sieve: ManageSieve Protocol.

Registered (user) port, 1024-49151 TCP

IANA assignment

Service nameProtoDescriptionAssigneeReference

sieve TCP ManageSieve Protocol - -

Linux: is anything listening on TCP 4190?

sudo ss -tlnp 'sport = :4190'

Linux / macOS: which process owns the port

sudo lsof -nP -i :4190

Older Linux / BSD (net-tools)

sudo netstat -tlnp | grep ':4190 '

Windows (Command Prompt)

netstat -ano | findstr :4190

Windows (PowerShell)

Get-NetTCPConnection -LocalPort 4190 -State Listen | Select LocalAddress,OwningProcess

From another machine

nc -vz -w 5 HOST 4190

From Windows

Test-NetConnection HOST -Port 4190

ufw

sudo ufw deny 4190/tcp

iptables

sudo iptables -A INPUT -p tcp --dport 4190 -j DROP

nftables

sudo nft add rule inet filter input tcp dport 4190 drop

Windows Firewall

New-NetFirewallRule -DisplayName 'Block TCP 4190' -Direction Inbound -Protocol TCP -LocalPort 4190 -Action Block

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