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Port 197 (dls)

IANA assigns port 197 to dls: Directory Location Service.

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

IANA assignment

Service nameProtoDescriptionAssigneeReference
dls TCP Directory Location Service - -
dls UDP Directory Location Service - -

Check what is listening on port 197

Linux: is anything listening on TCP 197?
sudo ss -tlnp 'sport = :197'
Linux: UDP 197
sudo ss -ulnp 'sport = :197'
Linux / macOS: which process owns the port
sudo lsof -nP -i :197
Older Linux / BSD (net-tools)
sudo netstat -tlnp | grep ':197 '
Windows (Command Prompt)
netstat -ano | findstr :197
Windows (PowerShell)
Get-NetTCPConnection -LocalPort 197 -State Listen | Select LocalAddress,OwningProcess

Test it from outside

From another machine
nc -vz -w 5 HOST 197
From Windows
Test-NetConnection HOST -Port 197
UDP probe (no reply does not prove it is closed)
nc -vzu -w 5 HOST 197

Block port 197 in the firewall

ufw
sudo ufw deny 197/tcp
iptables
sudo iptables -A INPUT -p tcp --dport 197 -j DROP
nftables
sudo nft add rule inet filter input tcp dport 197 drop
Windows Firewall
New-NetFirewallRule -DisplayName 'Block TCP 197' -Direction Inbound -Protocol TCP -LocalPort 197 -Action Block
ufw
sudo ufw deny 197/udp
iptables
sudo iptables -A INPUT -p udp --dport 197 -j DROP
nftables
sudo nft add rule inet filter input udp dport 197 drop
Windows Firewall
New-NetFirewallRule -DisplayName 'Block UDP 197' -Direction Inbound -Protocol UDP -LocalPort 197 -Action Block

Related ports

195dn6-nlm-aud196dn6-smm-red198dls-mon199smux

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