HTTPfy

Port 3351 (btrieve)

IANA assigns port 3351 to btrieve: Btrieve port.

Registered (user) port, 1024-49151 TCPUDP

IANA assignment

Service nameProtoDescriptionAssigneeReference
btrieve TCP Btrieve port - -
btrieve UDP Btrieve port - -

Check what is listening on port 3351

Linux: is anything listening on TCP 3351?
sudo ss -tlnp 'sport = :3351'
Linux: UDP 3351
sudo ss -ulnp 'sport = :3351'
Linux / macOS: which process owns the port
sudo lsof -nP -i :3351
Older Linux / BSD (net-tools)
sudo netstat -tlnp | grep ':3351 '
Windows (Command Prompt)
netstat -ano | findstr :3351
Windows (PowerShell)
Get-NetTCPConnection -LocalPort 3351 -State Listen | Select LocalAddress,OwningProcess

Test it from outside

From another machine
nc -vz -w 5 HOST 3351
From Windows
Test-NetConnection HOST -Port 3351
UDP probe (no reply does not prove it is closed)
nc -vzu -w 5 HOST 3351

Block port 3351 in the firewall

ufw
sudo ufw deny 3351/tcp
iptables
sudo iptables -A INPUT -p tcp --dport 3351 -j DROP
nftables
sudo nft add rule inet filter input tcp dport 3351 drop
Windows Firewall
New-NetFirewallRule -DisplayName 'Block TCP 3351' -Direction Inbound -Protocol TCP -LocalPort 3351 -Action Block
ufw
sudo ufw deny 3351/udp
iptables
sudo iptables -A INPUT -p udp --dport 3351 -j DROP
nftables
sudo nft add rule inet filter input udp dport 3351 drop
Windows Firewall
New-NetFirewallRule -DisplayName 'Block UDP 3351' -Direction Inbound -Protocol UDP -LocalPort 3351 -Action Block

Related ports

3349chevinservices3350findviatv3352ssql3353fatpipe

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