Hello.
FYI: When Dude discovers device with telnet service and keeps polling telnet, this may kill device management interface.
In my case device stops responding to telnet and http management. Traffic was unaffected.
This is devices manufacturers response about device management lock-up issue:
"The problem is the way how Dude probes the Telnet service. It doesn’t close the session correctly so it keeps open forever. The next probe opens the new session and so on and so forth. Finally the modem runs out of the resources and freezes. This would never happens if the client open and close the session correctly but it happens for such automatic probes. You can disable the telnet probe as the temporary solution."
In my case vendor will fix this in modem firmware.