Port 35355 ALTOVA-LM-DISC
Port 35355 has a different IANA assignment for each transport protocol: TCP altova-lm; UDP altova-lm-disc.
What is port 35355 used for?
Port 35355 carries a different IANA service on each transport protocol: TCP altova-lm; UDP altova-lm-disc. It sits above the registered range, where most numbers are transient client ports. A fixed high port is worth documenting precisely because tooling often assumes the default. The same port is also registered under altova-lm.
Each transport reaches a different service on this number, so match the protocol to the service you are diagnosing. A TCP check says nothing about a UDP listener on the same port, and the reverse is also true. Both transports still bind to the same number, which is why two processes can collide even when they use different protocols.
Use the commands below to confirm whether port 35355 is actually in use before you change firewall rules. Blocking the port stops new inbound traffic at the firewall, but it does not stop a local process from listening, and it does not remove the service from the machine.
Source: IANA Service Name and Transport Protocol Port Number Registry. Registered assignee: [Alexander_Falk_2].
Check and block port 35355
Copy-ready commands for the protocols assigned to this port. Run the check first, then block only what should not be reachable.
Check on Linux
sudo ss -tlpn 'sport = :35355'
sudo ss -ulpn 'sport = :35355'Check on Windows
Get-NetTCPConnection -LocalPort 35355 -State Listen -ErrorAction SilentlyContinue
Get-NetUDPEndpoint -LocalPort 35355 -ErrorAction SilentlyContinueBlock with UFW
sudo ufw deny 35355/tcp
sudo ufw deny 35355/udpBlock with iptables
sudo iptables -A INPUT -p tcp --dport 35355 -j DROP
sudo iptables -A INPUT -p udp --dport 35355 -j DROPThese commands are examples for a typical host. Check the listener before you change firewall rules, and persist iptables rules with iptables-save or netfilter-persistent. On Windows, use Windows Defender Firewall or New-NetFirewallRule for persistent blocks. The iptables rules here cover IPv4; mirror them with ip6tables if IPv6 is enabled.
Is port 35355 safe to expose?
This port is not on our curated list of services with a widely exploited profile. Exposure is only safe when the listening service is intended, patched and protected by a firewall. Keep the listening service patched and remove it if unused. A default-deny firewall policy with explicit allow rules is still the safest baseline.
Where port 35355 is usually used
Most traffic on port 35355 falls into these scenarios. The demo below is a safe way to confirm the listener before you change anything.
- Custom or vendor-specific services configured to use a fixed high number.
- Short-lived container or test environments that publish the port on the host.
- Firewall planning, since most other high ports are transient client ports.
Probe the port
Confirm something is listening before you debug the client. This checks a TCP handshake on the port.
nc -vz 127.0.0.1 35355Common problems with port 35355
Connection refused or timed out
Refused usually means the host is reachable but nothing is listening on port 35355. A timeout more often means a firewall drop, a wrong host or a service bound to a different interface.
Port already in use
Find the process holding the port with sudo ss -tlpn 'sport = :35355' or sudo lsof -i :35355. Stop that process or configure it to bind another port; killing it without identifying it can take down a production service.
Firewall rule did not survive a reboot
UFW and Windows Firewall keep rules across restarts. Raw iptables rules do not: save them with iptables-save or the netfilter-persistent package, and re-apply after upgrades that reset the ruleset.
The port is blocked but still reachable
A firewall rule filters inbound traffic; it does not close the listener. Confirm with the check command above and bind the service to 127.0.0.1 when only local clients need it.
Port 35355 at a glance
| Port number | 35355 |
|---|---|
| Service name | altova-lm-disc |
| Aliases | altova-lm |
| Transport protocol | TCP / UDP |
| Assignments by protocol |
|
| Category | Custom high ports |
| Range | High port (10001–65535) |
| Risk level | Standard/Low |
| Registered assignee | [Alexander_Falk_2] |
| Registry description | Altova License Management Discovery |
| Source | IANA Service Name and Transport Protocol Port Number Registry |
Frequently asked questions
What is port 35355 used for?
Port 35355 (ALTOVA-LM-DISC). The IANA registry assigns a different service on each transport protocol: TCP altova-lm; UDP altova-lm-disc.
How do I check if port 35355 is open?
On Linux run `sudo ss -tlpn 'sport = :35355'` and `sudo ss -ulpn 'sport = :35355'`. On Windows run `Get-NetTCPConnection -LocalPort 35355 -State Listen -ErrorAction SilentlyContinue` and `Get-NetUDPEndpoint -LocalPort 35355 -ErrorAction SilentlyContinue` in PowerShell. If the port is open, the output shows a process listening on port 35355; empty output usually means nothing is bound to it.
How do I block port 35355?
With UFW run `sudo ufw deny 35355/tcp` and `sudo ufw deny 35355/udp`. With iptables run `sudo iptables -A INPUT -p tcp --dport 35355 -j DROP` and `sudo iptables -A INPUT -p udp --dport 35355 -j DROP`. Persist the iptables rules with your distribution's netfilter-persistent or iptables-save tooling so they survive a reboot.
Is port 35355 safe to expose?
This port is not on our curated list of services with a widely exploited profile. Exposure is only safe when the listening service is intended, patched and protected by a firewall. Nevertheless, keep the listening service patched and remove it if unused. A default-deny firewall policy with explicit allow rules is still the safest baseline.
Related ports
Primary data: IANA Service Name and Transport Protocol Port Number Registry.
Last reviewed 2026-10-30 · Methodology · About · Privacy