HTTPfy

Port 1993 (snmp-tcp-port)

IANA assigns port 1993 to snmp-tcp-port: cisco SNMP TCP port.

Registered (user) port, 1024-49151 TCPUDP

IANA assignment

Service nameProtoDescriptionAssigneeReference
snmp-tcp-port TCP cisco SNMP TCP port - -
snmp-tcp-port UDP cisco SNMP TCP port - -

Check what is listening on port 1993

Linux: is anything listening on TCP 1993?
sudo ss -tlnp 'sport = :1993'
Linux: UDP 1993
sudo ss -ulnp 'sport = :1993'
Linux / macOS: which process owns the port
sudo lsof -nP -i :1993
Older Linux / BSD (net-tools)
sudo netstat -tlnp | grep ':1993 '
Windows (Command Prompt)
netstat -ano | findstr :1993
Windows (PowerShell)
Get-NetTCPConnection -LocalPort 1993 -State Listen | Select LocalAddress,OwningProcess

Test it from outside

From another machine
nc -vz -w 5 HOST 1993
From Windows
Test-NetConnection HOST -Port 1993
UDP probe (no reply does not prove it is closed)
nc -vzu -w 5 HOST 1993

Block port 1993 in the firewall

ufw
sudo ufw deny 1993/tcp
iptables
sudo iptables -A INPUT -p tcp --dport 1993 -j DROP
nftables
sudo nft add rule inet filter input tcp dport 1993 drop
Windows Firewall
New-NetFirewallRule -DisplayName 'Block TCP 1993' -Direction Inbound -Protocol TCP -LocalPort 1993 -Action Block
ufw
sudo ufw deny 1993/udp
iptables
sudo iptables -A INPUT -p udp --dport 1993 -j DROP
nftables
sudo nft add rule inet filter input udp dport 1993 drop
Windows Firewall
New-NetFirewallRule -DisplayName 'Block UDP 1993' -Direction Inbound -Protocol UDP -LocalPort 1993 -Action Block

Related ports

1991stun-p21992stun-p3, ipsendmsg1994stun-port1995perf-port

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