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Port 2139 (ias-auth)

IANA assigns port 2139 to ias-auth: IAS-AUTH.

Registered (user) port, 1024-49151 TCPUDP

IANA assignment

Service nameProtoDescriptionAssigneeReference
ias-auth TCP IAS-AUTH - -
ias-auth UDP IAS-AUTH - -

Check what is listening on port 2139

Linux: is anything listening on TCP 2139?
sudo ss -tlnp 'sport = :2139'
Linux: UDP 2139
sudo ss -ulnp 'sport = :2139'
Linux / macOS: which process owns the port
sudo lsof -nP -i :2139
Older Linux / BSD (net-tools)
sudo netstat -tlnp | grep ':2139 '
Windows (Command Prompt)
netstat -ano | findstr :2139
Windows (PowerShell)
Get-NetTCPConnection -LocalPort 2139 -State Listen | Select LocalAddress,OwningProcess

Test it from outside

From another machine
nc -vz -w 5 HOST 2139
From Windows
Test-NetConnection HOST -Port 2139
UDP probe (no reply does not prove it is closed)
nc -vzu -w 5 HOST 2139

Block port 2139 in the firewall

ufw
sudo ufw deny 2139/tcp
iptables
sudo iptables -A INPUT -p tcp --dport 2139 -j DROP
nftables
sudo nft add rule inet filter input tcp dport 2139 drop
Windows Firewall
New-NetFirewallRule -DisplayName 'Block TCP 2139' -Direction Inbound -Protocol TCP -LocalPort 2139 -Action Block
ufw
sudo ufw deny 2139/udp
iptables
sudo iptables -A INPUT -p udp --dport 2139 -j DROP
nftables
sudo nft add rule inet filter input udp dport 2139 drop
Windows Firewall
New-NetFirewallRule -DisplayName 'Block UDP 2139' -Direction Inbound -Protocol UDP -LocalPort 2139 -Action Block

Related ports

2137connect2138unbind-cluster2140ias-reg2141ias-admind

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