- Use strong credentials and TLS for signalling.
- Rate-limit registrations to stop extension scanning and toll fraud.
- Alert on unexpected chat protocols leaving servers (possible command and control).
Port 2703: SMS CHAT
Port 2703 is assigned by IANA to sms-chat (SMS CHAT).
2703
How sms-chat works
Voice & chatPort 2703 sets up the call (who calls whom), then the voice travels as a stream of audio packets.
- Transport
- TCP · UDP
- Exposure risk
- not rated depends on the program listening
- Encryption
- Unknownnot stated by the registry
- IANA status
- Assigned1 registered service
- Range
- Registered (1024-49151)
- Category
- Voice & chat
Is port 2703 dangerous?
We have no specific security note for port 2703. Its risk depends on the program actually listening on it. General advice for voice & chat services:
IANA registry entries for port 2703
| Service | Port | Transport | Description | Reference | Updated |
|---|---|---|---|---|---|
| sms-chat | 2703 | TCP, UDP | SMS CHAT | - | - |
// source: IANA service name and port number registry
Which program uses port 2703, and is it reachable?
Linux
sudo ss -ltnup 'sport = :2703' # process listening on 2703
sudo lsof -nP -i :2703macOS
sudo lsof -nP -i :2703
Windows (PowerShell)
Get-NetTCPConnection -LocalPort 2703 -State Listen | Select LocalAddress, OwningProcess Get-NetUDPEndpoint -LocalPort 2703 netstat -ano | findstr :2703
From another machine
nmap -p 2703 -sV <host> sudo nmap -sU -p 2703 <host> nc -zv <host> 2703
Block it in the firewall
sudo ufw deny 2703/tcp # Linux (ufw) New-NetFirewallRule -DisplayName "Block 2703" -Direction Inbound -LocalPort 2703 -Protocol TCP -Action Block # Windows
What is port 2703 used for?
Port 2703 is assigned by IANA to sms-chat (SMS CHAT).
Is port 2703 TCP or UDP?
Port 2703 is registered for TCP and UDP.
Is it safe to open port 2703?
It depends on the program that listens on it. Open it only for a service you know and only to the networks that need it. Use strong credentials and TLS for signalling.
How do I check if port 2703 is open?
On Linux run "ss -ltnup 'sport = :2703'", on macOS "lsof -nP -i :2703", and on Windows "netstat -ano | findstr :2703" to see the local process. From another machine, "nmap -p 2703 <host>" shows whether it is reachable.