HTTPfy

Port 348 (csi-sgwp)

IANA assigns port 348 to csi-sgwp: Cabletron Management Protocol.

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

IANA assignment

Service nameProtoDescriptionAssigneeReference
csi-sgwp TCP Cabletron Management Protocol - -
csi-sgwp UDP Cabletron Management Protocol - -

Check what is listening on port 348

Linux: is anything listening on TCP 348?
sudo ss -tlnp 'sport = :348'
Linux: UDP 348
sudo ss -ulnp 'sport = :348'
Linux / macOS: which process owns the port
sudo lsof -nP -i :348
Older Linux / BSD (net-tools)
sudo netstat -tlnp | grep ':348 '
Windows (Command Prompt)
netstat -ano | findstr :348
Windows (PowerShell)
Get-NetTCPConnection -LocalPort 348 -State Listen | Select LocalAddress,OwningProcess

Test it from outside

From another machine
nc -vz -w 5 HOST 348
From Windows
Test-NetConnection HOST -Port 348
UDP probe (no reply does not prove it is closed)
nc -vzu -w 5 HOST 348

Block port 348 in the firewall

ufw
sudo ufw deny 348/tcp
iptables
sudo iptables -A INPUT -p tcp --dport 348 -j DROP
nftables
sudo nft add rule inet filter input tcp dport 348 drop
Windows Firewall
New-NetFirewallRule -DisplayName 'Block TCP 348' -Direction Inbound -Protocol TCP -LocalPort 348 -Action Block
ufw
sudo ufw deny 348/udp
iptables
sudo iptables -A INPUT -p udp --dport 348 -j DROP
nftables
sudo nft add rule inet filter input udp dport 348 drop
Windows Firewall
New-NetFirewallRule -DisplayName 'Block UDP 348' -Direction Inbound -Protocol UDP -LocalPort 348 -Action Block

Related ports

346zserv347fatserv349mftp350matip-type-a

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