HTTPfy

Port 1242 (nmasoverip)

IANA assigns port 1242 to nmasoverip: NMAS over IP.

Registered (user) port, 1024-49151 TCPUDP

IANA assignment

Service nameProtoDescriptionAssigneeReference
nmasoverip TCP NMAS over IP Hal Henderson -
nmasoverip UDP NMAS over IP Hal Henderson -

Check what is listening on port 1242

Linux: is anything listening on TCP 1242?
sudo ss -tlnp 'sport = :1242'
Linux: UDP 1242
sudo ss -ulnp 'sport = :1242'
Linux / macOS: which process owns the port
sudo lsof -nP -i :1242
Older Linux / BSD (net-tools)
sudo netstat -tlnp | grep ':1242 '
Windows (Command Prompt)
netstat -ano | findstr :1242
Windows (PowerShell)
Get-NetTCPConnection -LocalPort 1242 -State Listen | Select LocalAddress,OwningProcess

Test it from outside

From another machine
nc -vz -w 5 HOST 1242
From Windows
Test-NetConnection HOST -Port 1242
UDP probe (no reply does not prove it is closed)
nc -vzu -w 5 HOST 1242

Block port 1242 in the firewall

ufw
sudo ufw deny 1242/tcp
iptables
sudo iptables -A INPUT -p tcp --dport 1242 -j DROP
nftables
sudo nft add rule inet filter input tcp dport 1242 drop
Windows Firewall
New-NetFirewallRule -DisplayName 'Block TCP 1242' -Direction Inbound -Protocol TCP -LocalPort 1242 -Action Block
ufw
sudo ufw deny 1242/udp
iptables
sudo iptables -A INPUT -p udp --dport 1242 -j DROP
nftables
sudo nft add rule inet filter input udp dport 1242 drop
Windows Firewall
New-NetFirewallRule -DisplayName 'Block UDP 1242' -Direction Inbound -Protocol UDP -LocalPort 1242 -Action Block

Related ports

1240instantia1241nessus1243serialgateway1244isbconference1

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