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Port 5618 (efr)

IANA assigns port 5618 to efr: Fiscal Registering Protocol.

Registered (user) port, 1024-49151 TCP

IANA assignment

Service nameProtoDescriptionAssigneeReference
efr TCP Fiscal Registering Protocol efsta IT Services GmbH -

Registry dates for this port: registered 2013-08-13, last modified 2022-02-02.

Check what is listening on port 5618

Linux: is anything listening on TCP 5618?
sudo ss -tlnp 'sport = :5618'
Linux / macOS: which process owns the port
sudo lsof -nP -i :5618
Older Linux / BSD (net-tools)
sudo netstat -tlnp | grep ':5618 '
Windows (Command Prompt)
netstat -ano | findstr :5618
Windows (PowerShell)
Get-NetTCPConnection -LocalPort 5618 -State Listen | Select LocalAddress,OwningProcess

Test it from outside

From another machine
nc -vz -w 5 HOST 5618
From Windows
Test-NetConnection HOST -Port 5618

Block port 5618 in the firewall

ufw
sudo ufw deny 5618/tcp
iptables
sudo iptables -A INPUT -p tcp --dport 5618 -j DROP
nftables
sudo nft add rule inet filter input tcp dport 5618 drop
Windows Firewall
New-NetFirewallRule -DisplayName 'Block TCP 5618' -Direction Inbound -Protocol TCP -LocalPort 5618 -Action Block

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