Port 198 (dls-mon)

IANA assigns port 198 to dls-mon: Directory Location Service Monitor.

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

IANA assignment

Service nameProtoDescriptionAssigneeReference

dls-mon TCP Directory Location Service Monitor Scott Bellew -

dls-mon UDP Directory Location Service Monitor Scott Bellew -

Linux: is anything listening on TCP 198?

sudo ss -tlnp 'sport = :198'

Linux: UDP 198

sudo ss -ulnp 'sport = :198'

Linux / macOS: which process owns the port

sudo lsof -nP -i :198

Older Linux / BSD (net-tools)

sudo netstat -tlnp | grep ':198 '

Windows (Command Prompt)

netstat -ano | findstr :198

Windows (PowerShell)

Get-NetTCPConnection -LocalPort 198 -State Listen | Select LocalAddress,OwningProcess

From another machine

nc -vz -w 5 HOST 198

From Windows

Test-NetConnection HOST -Port 198

UDP probe (no reply does not prove it is closed)

nc -vzu -w 5 HOST 198

ufw

sudo ufw deny 198/tcp

iptables

sudo iptables -A INPUT -p tcp --dport 198 -j DROP

nftables

sudo nft add rule inet filter input tcp dport 198 drop

Windows Firewall

New-NetFirewallRule -DisplayName 'Block TCP 198' -Direction Inbound -Protocol TCP -LocalPort 198 -Action Block

ufw

sudo ufw deny 198/udp

iptables

sudo iptables -A INPUT -p udp --dport 198 -j DROP

nftables

sudo nft add rule inet filter input udp dport 198 drop

Windows Firewall

New-NetFirewallRule -DisplayName 'Block UDP 198' -Direction Inbound -Protocol UDP -LocalPort 198 -Action Block

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Assignment data: IANA port number registry (public domain), retrieved 2026-11-10.