EHS6 LAN not seen in LAN | Telit Cinterion IoT Developer Community
May 24, 2018 - 3:59pm, 2905 views
Hi,
we had 1 EHS6 LAN module installed inside one company and it was connected to their local network. EHS6 was connected to switch and then to router, while PC was connected to some other switch or directly to router. PC issued AT commands over TELNET so that EHS6 sent SMS. Once it happened that there was power loss in the company and on reboot EHS6 acted as router(DHCP) and assigned IP to devices. This of course wasn’t acceptable so I disabled DHCP functionality. Everything worked OK for few weeks, but then suddenly PC couldn’t issue TELNET commands anymore. We tried to PING EHS6 from PC, but with no success. So we sent someone to the company to check what is wrong with the module. He could access web interface and ping it if he connected to the same switch as EHS6, but he couldn’t ping it from somewhere else in the network. Solution was that we did factory reset and set back the settings, after that it worked again for 1 week and same happened after that.
Module was then shipped to our office, where it’s plugged in our LAN and it works fine. So my question is, what setting could make him “invisible” to that company’s router?
Regards,
Jure
Hello,
At the first glance it looks like the problem in the customer's LAN as the EHS6 LAN port was accessible form the same switch and was not accessible from some other part of the network. At the same time it is also working well in your LAN. Maybe it's just a matter of proper configuration of the router.
Regards,
Bartłomiej
Hello,
I forgot to add that, if we would plug in laptop instead of EHS6 and set it to the same static IP as EHS it would be visible in the network.
Regards,
Jure
And have you also tried to unplug EHS6 LAN terminal and plug it again to verify if it can be visible from the other side of a router for some time after being connected?
Because if it is reachable form the same switch and at the same time it is not visible form some other device behind the router the first thing I can think of is that the router does not allow the connection or just does not 'know' about the EHS6 terminal.
Bartłomiej
Yes we did that and also took it's power source, but it didn't help. Only thing that helped was factory reset.
Regards,
Jure
Hello,
For me it still looks like the router could be to blame as it is possible to connect to the terminal directly via the switch and there are problems from behind the router and in your office there are no problems.
On the other hand you have described that resetting the terminal can also help (for some time) and the laptop with static IP is also accessible. But I don't have any idea what could cause such strange behavior.
To solve this problem I think that some tracing could be helpful - maybe even a PC with Wireshark connected to the same switch would be sufficient. Or consultation with the router administrator. Maybe you have any other observations like increased ping ***** or something else? BTW does it reply to ping from behind the router when it's working fine after factory reset? Maybe the router blocks pings.
Regards,
Bartłomiej
Hello,
PC with wireshark will be problematic, because I don't belive that company will alove us to check there LAN trafic.
I have no other observations at the momment. But yes, ping is working after factory reset.
Regards,
Jure
Hello Jure,
I think that tracing the subnetwork where the terminal is connected would be helpful to answer the question if the router may be to blame.
The other way could be troubleshooting the Linux system. The LAN functionality of the terminal is controlled by the additional processor with Linux OpenWrt system. You have the possibility to login there. Factory reset brings everything to factory state, all temporary files, routing tables, arp tables, everything is deleted. So if you suspect that there is a problem in the terminal you should do some debug and troubleshooting inside the Linux system and it's network interface. Maybe after some time from fresh installation something goes wrong there. And also try to ping the PC from LAN terminal.
Regards,
Bartłomiej