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Port 2821 (vrts-at-port)

IANA assigns port 2821 to vrts-at-port: VERITAS Authentication Service.

Registered (user) port, 1024-49151 TCPUDP

IANA assignment

Service nameProtoDescriptionAssigneeReference
vrts-at-port TCP VERITAS Authentication Service Stefan Winkel -
vrts-at-port UDP VERITAS Authentication Service Stefan Winkel -

Check what is listening on port 2821

Linux: is anything listening on TCP 2821?
sudo ss -tlnp 'sport = :2821'
Linux: UDP 2821
sudo ss -ulnp 'sport = :2821'
Linux / macOS: which process owns the port
sudo lsof -nP -i :2821
Older Linux / BSD (net-tools)
sudo netstat -tlnp | grep ':2821 '
Windows (Command Prompt)
netstat -ano | findstr :2821
Windows (PowerShell)
Get-NetTCPConnection -LocalPort 2821 -State Listen | Select LocalAddress,OwningProcess

Test it from outside

From another machine
nc -vz -w 5 HOST 2821
From Windows
Test-NetConnection HOST -Port 2821
UDP probe (no reply does not prove it is closed)
nc -vzu -w 5 HOST 2821

Block port 2821 in the firewall

ufw
sudo ufw deny 2821/tcp
iptables
sudo iptables -A INPUT -p tcp --dport 2821 -j DROP
nftables
sudo nft add rule inet filter input tcp dport 2821 drop
Windows Firewall
New-NetFirewallRule -DisplayName 'Block TCP 2821' -Direction Inbound -Protocol TCP -LocalPort 2821 -Action Block
ufw
sudo ufw deny 2821/udp
iptables
sudo iptables -A INPUT -p udp --dport 2821 -j DROP
nftables
sudo nft add rule inet filter input udp dport 2821 drop
Windows Firewall
New-NetFirewallRule -DisplayName 'Block UDP 2821' -Direction Inbound -Protocol UDP -LocalPort 2821 -Action Block

Related ports

2819fc-faultnotify2820univision2822ka0wuc2823cqg-netlan

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