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Port 3688 (simple-push-s)

IANA assigns port 3688 to simple-push-s: simple-push Secure.

Registered (user) port, 1024-49151 TCPUDP

IANA assignment

Service nameProtoDescriptionAssigneeReference
simple-push-s TCP simple-push Secure C Enrique Ortiz -
simple-push-s UDP simple-push Secure C Enrique Ortiz -

Registry dates for this port: registered 2003-01.

Check what is listening on port 3688

Linux: is anything listening on TCP 3688?
sudo ss -tlnp 'sport = :3688'
Linux: UDP 3688
sudo ss -ulnp 'sport = :3688'
Linux / macOS: which process owns the port
sudo lsof -nP -i :3688
Older Linux / BSD (net-tools)
sudo netstat -tlnp | grep ':3688 '
Windows (Command Prompt)
netstat -ano | findstr :3688
Windows (PowerShell)
Get-NetTCPConnection -LocalPort 3688 -State Listen | Select LocalAddress,OwningProcess

Test it from outside

From another machine
nc -vz -w 5 HOST 3688
From Windows
Test-NetConnection HOST -Port 3688
UDP probe (no reply does not prove it is closed)
nc -vzu -w 5 HOST 3688

Block port 3688 in the firewall

ufw
sudo ufw deny 3688/tcp
iptables
sudo iptables -A INPUT -p tcp --dport 3688 -j DROP
nftables
sudo nft add rule inet filter input tcp dport 3688 drop
Windows Firewall
New-NetFirewallRule -DisplayName 'Block TCP 3688' -Direction Inbound -Protocol TCP -LocalPort 3688 -Action Block
ufw
sudo ufw deny 3688/udp
iptables
sudo iptables -A INPUT -p udp --dport 3688 -j DROP
nftables
sudo nft add rule inet filter input udp dport 3688 drop
Windows Firewall
New-NetFirewallRule -DisplayName 'Block UDP 3688' -Direction Inbound -Protocol UDP -LocalPort 3688 -Action Block

Related ports

3686tnmpv23687simple-push3689daap3690Subversion (svnserve)

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