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Port 112 (mcidas)

IANA assigns port 112 to mcidas: McIDAS Data Transmission Protocol.

Well-known (system) port, 0-1023 TCPUDP

IANA assignment

Service nameProtoDescriptionAssigneeReference
mcidas TCP McIDAS Data Transmission Protocol Glenn Davis -
mcidas UDP McIDAS Data Transmission Protocol Glenn Davis -

Check what is listening on port 112

Linux: is anything listening on TCP 112?
sudo ss -tlnp 'sport = :112'
Linux: UDP 112
sudo ss -ulnp 'sport = :112'
Linux / macOS: which process owns the port
sudo lsof -nP -i :112
Older Linux / BSD (net-tools)
sudo netstat -tlnp | grep ':112 '
Windows (Command Prompt)
netstat -ano | findstr :112
Windows (PowerShell)
Get-NetTCPConnection -LocalPort 112 -State Listen | Select LocalAddress,OwningProcess

Test it from outside

From another machine
nc -vz -w 5 HOST 112
From Windows
Test-NetConnection HOST -Port 112
UDP probe (no reply does not prove it is closed)
nc -vzu -w 5 HOST 112

Block port 112 in the firewall

ufw
sudo ufw deny 112/tcp
iptables
sudo iptables -A INPUT -p tcp --dport 112 -j DROP
nftables
sudo nft add rule inet filter input tcp dport 112 drop
Windows Firewall
New-NetFirewallRule -DisplayName 'Block TCP 112' -Direction Inbound -Protocol TCP -LocalPort 112 -Action Block
ufw
sudo ufw deny 112/udp
iptables
sudo iptables -A INPUT -p udp --dport 112 -j DROP
nftables
sudo nft add rule inet filter input udp dport 112 drop
Windows Firewall
New-NetFirewallRule -DisplayName 'Block UDP 112' -Direction Inbound -Protocol UDP -LocalPort 112 -Action Block

Related ports

110POP3111rpcbind / portmapper113Ident115sftp

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