Since some months, I frequently experience that clients connected to the internet via a RUTX11 unit lose internet connection.
Issue
- Connection to internet is lost.
- The duration varies between a few seconds up towards perhaps a minute.
- Sometimes the outage is repeated after a short period (minutes), sometimes the connection is stable over a longer period. That is, no clearly identifiable pattern.
- The log files in the RUTX11 unit shows no events for when the connection is lost or re-established.
- During outage:
- Clients get ping responses from the RUTX11 unit but not from ip-addresses outside my network (e.g. 1.1.1.1 or 8.8.8.8).
- The "Data connection state" (in Status > Network > Mobile) displays "Connected".
- The "Mobile signal strength" graph (in Status > Realtime data > Mobile signal) displays unchanged mobile signal parameters.
Topology
Internet > RUTX11 [bridge mode] > Router > Switch > Clients
Performed troubleshooting
- Simultaneous ping command to three addresses (one to a public DNS server, one to the RUTX11 unit and one to the router) results in the public DNS server not responding during the outage, but both the modem (RUTX11) and the downstream router continued to respond.
- RUTX11 log displayed in the user interface shows no entries related to the issue.
- I've tried with two different SIM cards (same mobile operator). The issue occurs with both.
- I've contacted the mobile operator's technical support but they cannot see any anomalies.
- I have temporarily switched over to using a backup RUT240. I have no disconnect issues when using the SIM cards in this unit.
The above leads me to the conclusion that the source of the issue is the RUTX11 unit (or its firmware).
Firmware information
The unit is currently running firmware RUTX_R_00.07.02.7, but the issue has been observed with previously installed versions RUTX_R_00.07.01.2, RUTX_R_00.07.01.5 and RUTX_R_00.07.01.6.