HTTPfy

Port 3603 (int-rcv-cntrl)

IANA assigns port 3603 to int-rcv-cntrl: Integrated Rcvr Control.

Registered (user) port, 1024-49151 TCPUDP

IANA assignment

Service nameProtoDescriptionAssigneeReference
int-rcv-cntrl TCP Integrated Rcvr Control Dave Stone -
int-rcv-cntrl UDP Integrated Rcvr Control Dave Stone -

Registry dates for this port: registered 2002-09.

Check what is listening on port 3603

Linux: is anything listening on TCP 3603?
sudo ss -tlnp 'sport = :3603'
Linux: UDP 3603
sudo ss -ulnp 'sport = :3603'
Linux / macOS: which process owns the port
sudo lsof -nP -i :3603
Older Linux / BSD (net-tools)
sudo netstat -tlnp | grep ':3603 '
Windows (Command Prompt)
netstat -ano | findstr :3603
Windows (PowerShell)
Get-NetTCPConnection -LocalPort 3603 -State Listen | Select LocalAddress,OwningProcess

Test it from outside

From another machine
nc -vz -w 5 HOST 3603
From Windows
Test-NetConnection HOST -Port 3603
UDP probe (no reply does not prove it is closed)
nc -vzu -w 5 HOST 3603

Block port 3603 in the firewall

ufw
sudo ufw deny 3603/tcp
iptables
sudo iptables -A INPUT -p tcp --dport 3603 -j DROP
nftables
sudo nft add rule inet filter input tcp dport 3603 drop
Windows Firewall
New-NetFirewallRule -DisplayName 'Block TCP 3603' -Direction Inbound -Protocol TCP -LocalPort 3603 -Action Block
ufw
sudo ufw deny 3603/udp
iptables
sudo iptables -A INPUT -p udp --dport 3603 -j DROP
nftables
sudo nft add rule inet filter input udp dport 3603 drop
Windows Firewall
New-NetFirewallRule -DisplayName 'Block UDP 3603' -Direction Inbound -Protocol UDP -LocalPort 3603 -Action Block

Related ports

3601visinet-gui3602infiniswitchcl3604bmc-jmx-port3605comcam-io

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