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Port 2857 (simctlp)

IANA assigns port 2857 to simctlp: SimCtIP.

Registered (user) port, 1024-49151 TCPUDP

IANA assignment

Service nameProtoDescriptionAssigneeReference
simctlp TCP SimCtIP Christian Zietz -
simctlp UDP SimCtIP Christian Zietz -

Check what is listening on port 2857

Linux: is anything listening on TCP 2857?
sudo ss -tlnp 'sport = :2857'
Linux: UDP 2857
sudo ss -ulnp 'sport = :2857'
Linux / macOS: which process owns the port
sudo lsof -nP -i :2857
Older Linux / BSD (net-tools)
sudo netstat -tlnp | grep ':2857 '
Windows (Command Prompt)
netstat -ano | findstr :2857
Windows (PowerShell)
Get-NetTCPConnection -LocalPort 2857 -State Listen | Select LocalAddress,OwningProcess

Test it from outside

From another machine
nc -vz -w 5 HOST 2857
From Windows
Test-NetConnection HOST -Port 2857
UDP probe (no reply does not prove it is closed)
nc -vzu -w 5 HOST 2857

Block port 2857 in the firewall

ufw
sudo ufw deny 2857/tcp
iptables
sudo iptables -A INPUT -p tcp --dport 2857 -j DROP
nftables
sudo nft add rule inet filter input tcp dport 2857 drop
Windows Firewall
New-NetFirewallRule -DisplayName 'Block TCP 2857' -Direction Inbound -Protocol TCP -LocalPort 2857 -Action Block
ufw
sudo ufw deny 2857/udp
iptables
sudo iptables -A INPUT -p udp --dport 2857 -j DROP
nftables
sudo nft add rule inet filter input udp dport 2857 drop
Windows Firewall
New-NetFirewallRule -DisplayName 'Block UDP 2857' -Direction Inbound -Protocol UDP -LocalPort 2857 -Action Block

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