LTE modem as failover internet

MihaAlpod

I am trying to set up LTE modem (Yealink B535-333) as failover internet on my SonicWall TZ500. My mobile internet provider provided a static IP address for on SIM card.

I've put the modem in bridge mode and tested it on my computer. It worked perfectly - I get a public static IP address assigned from my provider, can ping and access computer from internet.

When I connected the modem as WAN port on SonicWall with DHCP I get internet for about 5 minutes (pingable from internet) and than it stops working. If I use the same IP as static I get about 8 pings worth and than it fails.

Any idea why?

Ajishlal

Try to adjust the WAN interface MTU value.

https://www.sonicwall.com/support/knowledge-base/how-can-i-determine-the-mtu-size-of-wan-interfaces-to-optimize-throughput/170504812146650/