HTTPfy

Port 1557 (arbortext-lm)

IANA assigns port 1557 to arbortext-lm: ArborText License Manager.

Registered (user) port, 1024-49151 TCPUDP

IANA assignment

Service nameProtoDescriptionAssigneeReference
arbortext-lm TCP ArborText License Manager David J Wilson -
arbortext-lm UDP ArborText License Manager David J Wilson -

Check what is listening on port 1557

Linux: is anything listening on TCP 1557?
sudo ss -tlnp 'sport = :1557'
Linux: UDP 1557
sudo ss -ulnp 'sport = :1557'
Linux / macOS: which process owns the port
sudo lsof -nP -i :1557
Older Linux / BSD (net-tools)
sudo netstat -tlnp | grep ':1557 '
Windows (Command Prompt)
netstat -ano | findstr :1557
Windows (PowerShell)
Get-NetTCPConnection -LocalPort 1557 -State Listen | Select LocalAddress,OwningProcess

Test it from outside

From another machine
nc -vz -w 5 HOST 1557
From Windows
Test-NetConnection HOST -Port 1557
UDP probe (no reply does not prove it is closed)
nc -vzu -w 5 HOST 1557

Block port 1557 in the firewall

ufw
sudo ufw deny 1557/tcp
iptables
sudo iptables -A INPUT -p tcp --dport 1557 -j DROP
nftables
sudo nft add rule inet filter input tcp dport 1557 drop
Windows Firewall
New-NetFirewallRule -DisplayName 'Block TCP 1557' -Direction Inbound -Protocol TCP -LocalPort 1557 -Action Block
ufw
sudo ufw deny 1557/udp
iptables
sudo iptables -A INPUT -p udp --dport 1557 -j DROP
nftables
sudo nft add rule inet filter input udp dport 1557 drop
Windows Firewall
New-NetFirewallRule -DisplayName 'Block UDP 1557' -Direction Inbound -Protocol UDP -LocalPort 1557 -Action Block

Related ports

1555livelan1556veritas-pbx, veritas_pbx1558xingmpeg1559web2host

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