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Port 196 (dn6-smm-red)

IANA assigns port 196 to dn6-smm-red: DNSIX Session Mgt Module Audit Redir.

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

IANA assignment

Service nameProtoDescriptionAssigneeReference
dn6-smm-red TCP DNSIX Session Mgt Module Audit Redir Lawrence Lebahn -
dn6-smm-red UDP DNSIX Session Mgt Module Audit Redir Lawrence Lebahn -

Check what is listening on port 196

Linux: is anything listening on TCP 196?
sudo ss -tlnp 'sport = :196'
Linux: UDP 196
sudo ss -ulnp 'sport = :196'
Linux / macOS: which process owns the port
sudo lsof -nP -i :196
Older Linux / BSD (net-tools)
sudo netstat -tlnp | grep ':196 '
Windows (Command Prompt)
netstat -ano | findstr :196
Windows (PowerShell)
Get-NetTCPConnection -LocalPort 196 -State Listen | Select LocalAddress,OwningProcess

Test it from outside

From another machine
nc -vz -w 5 HOST 196
From Windows
Test-NetConnection HOST -Port 196
UDP probe (no reply does not prove it is closed)
nc -vzu -w 5 HOST 196

Block port 196 in the firewall

ufw
sudo ufw deny 196/tcp
iptables
sudo iptables -A INPUT -p tcp --dport 196 -j DROP
nftables
sudo nft add rule inet filter input tcp dport 196 drop
Windows Firewall
New-NetFirewallRule -DisplayName 'Block TCP 196' -Direction Inbound -Protocol TCP -LocalPort 196 -Action Block
ufw
sudo ufw deny 196/udp
iptables
sudo iptables -A INPUT -p udp --dport 196 -j DROP
nftables
sudo nft add rule inet filter input udp dport 196 drop
Windows Firewall
New-NetFirewallRule -DisplayName 'Block UDP 196' -Direction Inbound -Protocol UDP -LocalPort 196 -Action Block

Related ports

194IRC (IANA)195dn6-nlm-aud197dls198dls-mon

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