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Port 346 (zserv)

IANA assigns port 346 to zserv: Zebra server.

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

IANA assignment

Service nameProtoDescriptionAssigneeReference
zserv TCP Zebra server - -
zserv UDP Zebra server - -

Check what is listening on port 346

Linux: is anything listening on TCP 346?
sudo ss -tlnp 'sport = :346'
Linux: UDP 346
sudo ss -ulnp 'sport = :346'
Linux / macOS: which process owns the port
sudo lsof -nP -i :346
Older Linux / BSD (net-tools)
sudo netstat -tlnp | grep ':346 '
Windows (Command Prompt)
netstat -ano | findstr :346
Windows (PowerShell)
Get-NetTCPConnection -LocalPort 346 -State Listen | Select LocalAddress,OwningProcess

Test it from outside

From another machine
nc -vz -w 5 HOST 346
From Windows
Test-NetConnection HOST -Port 346
UDP probe (no reply does not prove it is closed)
nc -vzu -w 5 HOST 346

Block port 346 in the firewall

ufw
sudo ufw deny 346/tcp
iptables
sudo iptables -A INPUT -p tcp --dport 346 -j DROP
nftables
sudo nft add rule inet filter input tcp dport 346 drop
Windows Firewall
New-NetFirewallRule -DisplayName 'Block TCP 346' -Direction Inbound -Protocol TCP -LocalPort 346 -Action Block
ufw
sudo ufw deny 346/udp
iptables
sudo iptables -A INPUT -p udp --dport 346 -j DROP
nftables
sudo nft add rule inet filter input udp dport 346 drop
Windows Firewall
New-NetFirewallRule -DisplayName 'Block UDP 346' -Direction Inbound -Protocol UDP -LocalPort 346 -Action Block

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