FOR TIPS, gUIDES & TUTORIALS

subscribe to our Youtube

GO TO YOUTUBE

14455 questions

17168 answers

28195 comments

0 members

We are migrating to our new platform at https://community.teltonika.lt. Moving forward, you can continue discussions on this new platform. This current platform will be temporarily maintained for reference purposes.
0 votes
244 views 0 comments
by anonymous
I have a setup with a RUT955, and I am trying to use it to remotely connect to an end device.
When connected with cable direct to the RUT955, I am able to ping both an IP camera and my end device.
However, when connected to the RUT955 over openVPN I am only able to ping the IP camera but not my end device.

The IP camera is only attached to ensure the RUT955 and its configuration is setup correct.

Because the IP camera is working through the openVPN the basic configuration needs to be correct.
The IP camera has a DHCP leased IP address, the end device has a static IP address.

The basic settings are:
IP range on the RUT955 is LAN is 192.168.82.x, IP of the RUT955 is 192.168.82.1
Camera IP is 192.168.82.161, received from DHCP
End device IP is 192.168.82.247, static IP address
Desktop computer openVPN lan IP = 192.168.255.6

After a lot of digging, I can only come up with the following:
using the ping command from my desktop, over openVPN, to the IP camera has this on the TCPDump:
>>12:11:35.774957 ARP, Request who-has 192.168.82.1 tell 192.168.82.161, length 46
>>12:11:35.775095 ARP, Reply 192.168.82.1 is-at xx:xx:xx:xx:xx:xx, length 28
>>12:12:41.321072 IP 192.168.255.6 > 192.168.82.161: ICMP echo request, id 1, seq 558, length 40
>>12:12:41.323900 IP 192.168.82.161 > 192.168.255.6: ICMP echo reply, id 1, seq 558, length 40
>>12:12:42.359813 IP 192.168.255.6 > 192.168.82.161: ICMP echo request, id 1, seq 559, length 40
>>12:12:42.360217 IP 192.168.82.161 > 192.168.255.6: ICMP echo reply, id 1, seq 559, length 40
>>12:12:42.568734 IP 192.168.82.161.1031 > 239.255.255.250.1900: UDP, length 261
>>12:12:42.569698 IP 192.168.82.161.1031 > 239.255.255.250.1900: UDP, length 255
>>12:12:43.359735 IP 192.168.255.6 > 192.168.82.161: ICMP echo request, id 1, seq 560, length 40
>>12:12:43.360199 IP 192.168.82.161 > 192.168.255.6: ICMP echo reply, id 1, seq 560, length 40
>>12:12:44.360608 IP 192.168.255.6 > 192.168.82.161: ICMP echo request, id 1, seq 561, length 40
>>12:12:44.361116 IP 192.168.82.161 > 192.168.255.6: ICMP echo reply, id 1, seq 561, length 40
>>12:12:45.910002 IP 192.168.82.247.1740 > 192.168.82.255.1740: UDP, length 8
>>12:12:45.910223 IP 192.168.82.247.1740 > 192.168.82.255.1741: UDP, length 8
>>12:12:45.910328 IP 192.168.82.247.1740 > 192.168.82.255.1742: UDP, length 8
>>12:12:45.910859 IP 192.168.82.247.1740 > 192.168.82.255.1743: UDP, length 8
>>12:12:46.318132 ARP, Request who-has 192.168.82.1 tell 192.168.82.161, length 46
>>12:12:46.318282 ARP, Reply 192.168.82.1 is-at xx:xx:xx:xx:xx:xx, length 28
>>12:12:46.377136 ARP, Request who-has 192.168.82.161 tell 192.168.82.1, length 28
>>12:12:46.377730 ARP, Reply 192.168.82.161 is-at xx:xx:xx:xx:xx:xx, length 46

This results in 4 packages sent and received, and the IP camera is operational over the openVPN connection (double check)

Now the ping command for 192.168.82.247, the end device it is all about:
>>12:23:11.901310 IP 192.168.255.6 > 192.168.82.247: ICMP echo request, id 1, seq 566, length 40
>>12:23:11.902360 ARP, Request who-has 192.168.82.21 tell 192.168.82.247, length 46
>>12:23:12.523523 IP 192.168.82.161.1031 > 239.255.255.250.1900: UDP, length 261
>>12:23:12.524057 IP 192.168.82.161.1031 > 239.255.255.250.1900: UDP, length 255
>>12:23:12.883466 ARP, Request who-has 192.168.82.21 tell 192.168.82.247, length 46
>>12:23:13.883901 ARP, Request who-has 192.168.82.21 tell 192.168.82.247, length 46
>>12:23:14.885048 ARP, Request who-has 192.168.82.21 tell 192.168.82.247, length 46
>>12:23:15.884782 ARP, Request who-has 192.168.82.21 tell 192.168.82.247, length 46
>>12:23:16.781163 IP 192.168.255.6 > 192.168.82.247: ICMP echo request, id 1, seq 567, length 40
>>12:23:16.905106 ARP, Request who-has 192.168.82.247 tell 192.168.82.1, length 28
>>12:23:16.906730 ARP, Reply 192.168.82.247 is-at xx:xx:xx:xx:xx:xx, length 46
>>12:23:21.780848 IP 192.168.255.6 > 192.168.82.247: ICMP echo request, id 1, seq 568, length 40
>>12:23:21.782760 ARP, Request who-has 192.168.82.21 tell 192.168.82.247, length 46
>>12:23:21.890640 ARP, Request who-has 192.168.82.21 tell 192.168.82.247, length 46
>>12:23:22.892457 ARP, Request who-has 192.168.82.21 tell 192.168.82.247, length 46
>>12:23:23.892422 ARP, Request who-has 192.168.82.21 tell 192.168.82.247, length 46\
>>12:23:24.892443 ARP, Request who-has 192.168.82.21 tell 192.168.82.247, length 46
>>12:23:26.780968 IP 192.168.255.6 > 192.168.82.247: ICMP echo request, id 1, seq 569, length 40
>>12:23:26.782188 ARP, Request who-has 192.168.82.21 tell 192.168.82.247, length 46
>>12:23:26.894120 ARP, Request who-has 192.168.82.21 tell 192.168.82.247, length 46
>>12:23:27.894077 ARP, Request who-has 192.168.82.21 tell 192.168.82.247, length 46
>>12:23:28.389174 IP 192.168.82.161.44421 > 122.248.252.67.8765: UDP, length 4
>>12:23:28.894094 ARP, Request who-has 192.168.82.21 tell 192.168.82.247, length 46
>>12:23:29.893946 ARP, Request who-has 192.168.82.21 tell 192.168.82.247, length 46

My assumption is, there is something wrong in the ARP table, where seems to be referred to 192.168.82.21 ?!?!? i.s.o. 192.168.82.1
I cannot seem to find any setting with a reference to the .21 IP address and I cannot get the ARP list on my screen.

I now have a few questions, first of all the most obvious:
- Does anyone know what is wrong and how to fix it?
- How can I see the contents of the ARP table?

If any vital info is missing, please let me know and I will add this!

appreciating any help,

kind regards,

Sjoerd van Veenen

1 Answer

+1 vote
by anonymous

Hi Sjoerd,

Try configuring static lease for the End device and make sure that the end device allows ping to all the WAN devices such as the DESKTOP computer with OpenVPN connection.
https://wiki.teltonika-networks.com/view/RUT955_Interfaces#Static_Lease
To allow a ping connection, please configure the end device's firewall inbound rule to allow ICMP traffic.

To check the ARP table, please use the below command:
arp -a

you can share those results with me via private message.

 

Regards
Raman