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Port 2704 (sms-remctrl)

IANA assigns port 2704 to sms-remctrl: SMS REMCTRL.

Registered (user) port, 1024-49151 TCPUDP

IANA assignment

Service nameProtoDescriptionAssigneeReference
sms-remctrl TCP SMS REMCTRL Tom Friend -
sms-remctrl UDP SMS REMCTRL Tom Friend -

Check what is listening on port 2704

Linux: is anything listening on TCP 2704?
sudo ss -tlnp 'sport = :2704'
Linux: UDP 2704
sudo ss -ulnp 'sport = :2704'
Linux / macOS: which process owns the port
sudo lsof -nP -i :2704
Older Linux / BSD (net-tools)
sudo netstat -tlnp | grep ':2704 '
Windows (Command Prompt)
netstat -ano | findstr :2704
Windows (PowerShell)
Get-NetTCPConnection -LocalPort 2704 -State Listen | Select LocalAddress,OwningProcess

Test it from outside

From another machine
nc -vz -w 5 HOST 2704
From Windows
Test-NetConnection HOST -Port 2704
UDP probe (no reply does not prove it is closed)
nc -vzu -w 5 HOST 2704

Block port 2704 in the firewall

ufw
sudo ufw deny 2704/tcp
iptables
sudo iptables -A INPUT -p tcp --dport 2704 -j DROP
nftables
sudo nft add rule inet filter input tcp dport 2704 drop
Windows Firewall
New-NetFirewallRule -DisplayName 'Block TCP 2704' -Direction Inbound -Protocol TCP -LocalPort 2704 -Action Block
ufw
sudo ufw deny 2704/udp
iptables
sudo iptables -A INPUT -p udp --dport 2704 -j DROP
nftables
sudo nft add rule inet filter input udp dport 2704 drop
Windows Firewall
New-NetFirewallRule -DisplayName 'Block UDP 2704' -Direction Inbound -Protocol UDP -LocalPort 2704 -Action Block

Related ports

2702sms-xfer2703sms-chat2705sds-admin2706ncdmirroring

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