Port 45045 (synctest)

IANA assigns port 45045 to synctest: Remote application control protocol.

Registered (user) port, 1024-49151 TCP

IANA assignment

Service nameProtoDescriptionAssigneeReference

synctest TCP Remote application control protocol Eleks Ltd -

Registry dates for this port: registered 2013-04-08.

Linux: is anything listening on TCP 45045?

sudo ss -tlnp 'sport = :45045'

Linux / macOS: which process owns the port

sudo lsof -nP -i :45045

Older Linux / BSD (net-tools)

sudo netstat -tlnp | grep ':45045 '

Windows (Command Prompt)

netstat -ano | findstr :45045

Windows (PowerShell)

Get-NetTCPConnection -LocalPort 45045 -State Listen | Select LocalAddress,OwningProcess

From another machine

nc -vz -w 5 HOST 45045

From Windows

Test-NetConnection HOST -Port 45045

ufw

sudo ufw deny 45045/tcp

iptables

sudo iptables -A INPUT -p tcp --dport 45045 -j DROP

nftables

sudo nft add rule inet filter input tcp dport 45045 drop

Windows Firewall

New-NetFirewallRule -DisplayName 'Block TCP 45045' -Direction Inbound -Protocol TCP -LocalPort 45045 -Action Block

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