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Port 1101 (pt2-discover)

IANA assigns port 1101 to pt2-discover: PT2-DISCOVER.

Registered (user) port, 1024-49151 TCPUDP

IANA assignment

Service nameProtoDescriptionAssigneeReference
pt2-discover TCP PT2-DISCOVER Ralph Kammerlander -
pt2-discover UDP PT2-DISCOVER Ralph Kammerlander -

Check what is listening on port 1101

Linux: is anything listening on TCP 1101?
sudo ss -tlnp 'sport = :1101'
Linux: UDP 1101
sudo ss -ulnp 'sport = :1101'
Linux / macOS: which process owns the port
sudo lsof -nP -i :1101
Older Linux / BSD (net-tools)
sudo netstat -tlnp | grep ':1101 '
Windows (Command Prompt)
netstat -ano | findstr :1101
Windows (PowerShell)
Get-NetTCPConnection -LocalPort 1101 -State Listen | Select LocalAddress,OwningProcess

Test it from outside

From another machine
nc -vz -w 5 HOST 1101
From Windows
Test-NetConnection HOST -Port 1101
UDP probe (no reply does not prove it is closed)
nc -vzu -w 5 HOST 1101

Block port 1101 in the firewall

ufw
sudo ufw deny 1101/tcp
iptables
sudo iptables -A INPUT -p tcp --dport 1101 -j DROP
nftables
sudo nft add rule inet filter input tcp dport 1101 drop
Windows Firewall
New-NetFirewallRule -DisplayName 'Block TCP 1101' -Direction Inbound -Protocol TCP -LocalPort 1101 -Action Block
ufw
sudo ufw deny 1101/udp
iptables
sudo iptables -A INPUT -p udp --dport 1101 -j DROP
nftables
sudo nft add rule inet filter input udp dport 1101 drop
Windows Firewall
New-NetFirewallRule -DisplayName 'Block UDP 1101' -Direction Inbound -Protocol UDP -LocalPort 1101 -Action Block

Related ports

1099Java RMI registry1100mctp1102adobeserver-11103adobeserver-2

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