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Port 4028 (dtserver-port)

IANA assigns port 4028 to dtserver-port: DTServer Port.

Registered (user) port, 1024-49151 TCPUDP

IANA assignment

Service nameProtoDescriptionAssigneeReference
dtserver-port TCP DTServer Port Stephen Aikins -
dtserver-port UDP DTServer Port Stephen Aikins -

Check what is listening on port 4028

Linux: is anything listening on TCP 4028?
sudo ss -tlnp 'sport = :4028'
Linux: UDP 4028
sudo ss -ulnp 'sport = :4028'
Linux / macOS: which process owns the port
sudo lsof -nP -i :4028
Older Linux / BSD (net-tools)
sudo netstat -tlnp | grep ':4028 '
Windows (Command Prompt)
netstat -ano | findstr :4028
Windows (PowerShell)
Get-NetTCPConnection -LocalPort 4028 -State Listen | Select LocalAddress,OwningProcess

Test it from outside

From another machine
nc -vz -w 5 HOST 4028
From Windows
Test-NetConnection HOST -Port 4028
UDP probe (no reply does not prove it is closed)
nc -vzu -w 5 HOST 4028

Block port 4028 in the firewall

ufw
sudo ufw deny 4028/tcp
iptables
sudo iptables -A INPUT -p tcp --dport 4028 -j DROP
nftables
sudo nft add rule inet filter input tcp dport 4028 drop
Windows Firewall
New-NetFirewallRule -DisplayName 'Block TCP 4028' -Direction Inbound -Protocol TCP -LocalPort 4028 -Action Block
ufw
sudo ufw deny 4028/udp
iptables
sudo iptables -A INPUT -p udp --dport 4028 -j DROP
nftables
sudo nft add rule inet filter input udp dport 4028 drop
Windows Firewall
New-NetFirewallRule -DisplayName 'Block UDP 4028' -Direction Inbound -Protocol UDP -LocalPort 4028 -Action Block

Related ports

4026as-debug4027bxp4029ip-qsig4030jdmn-port

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