Port 33434 (traceroute)

IANA assigns port 33434 to traceroute: traceroute use.

Registered (user) port, 1024-49151 TCPUDP

IANA assignment

Service nameProtoDescriptionAssigneeReference

traceroute TCP traceroute use IANA -

traceroute UDP traceroute use IANA -

Linux: is anything listening on TCP 33434?

sudo ss -tlnp 'sport = :33434'

Linux: UDP 33434

sudo ss -ulnp 'sport = :33434'

Linux / macOS: which process owns the port

sudo lsof -nP -i :33434

Older Linux / BSD (net-tools)

sudo netstat -tlnp | grep ':33434 '

Windows (Command Prompt)

netstat -ano | findstr :33434

Windows (PowerShell)

Get-NetTCPConnection -LocalPort 33434 -State Listen | Select LocalAddress,OwningProcess

From another machine

nc -vz -w 5 HOST 33434

From Windows

Test-NetConnection HOST -Port 33434

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

nc -vzu -w 5 HOST 33434

ufw

sudo ufw deny 33434/tcp

iptables

sudo iptables -A INPUT -p tcp --dport 33434 -j DROP

nftables

sudo nft add rule inet filter input tcp dport 33434 drop

Windows Firewall

New-NetFirewallRule -DisplayName 'Block TCP 33434' -Direction Inbound -Protocol TCP -LocalPort 33434 -Action Block

ufw

sudo ufw deny 33434/udp

iptables

sudo iptables -A INPUT -p udp --dport 33434 -j DROP

nftables

sudo nft add rule inet filter input udp dport 33434 drop

Windows Firewall

New-NetFirewallRule -DisplayName 'Block UDP 33434' -Direction Inbound -Protocol UDP -LocalPort 33434 -Action Block

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