Cellular failover issues

[dsekely_brs]

I am experiencing these issues when testing our cellular failover on a MX84 with a UML290 and USB730L.

Both cellular devices work perfectly when connected to a laptop and are setup to connect automatically.

When plugged into the MX84 they both are in the ready state and when I disconnect primary WAN the MX84 does fail over to cellular modem but I am not able to browse to any new websites.  The pages just time out.

If I happen to have websites open prior to the failover I am able to browse through the sub pages but any links to pages outside of that site time out as well.

While on cellular failover I can ping and trace route to any website from my workstation.  I am also able to get emails and instant messages to come through.

I was able to test the device in another MX84 that I replicated as much as possible the configuration from the MX having the issue above and the device worked without any issues.

What settings would be a good starting point to review given the non working behavior above?

[PhilipDAth]

It sounds to me like DNS is failing.

When running on celluar and you do an nslookup for a site you have not been too - does that fail?

Are you using manually assigned DNS servers by chance?

[dsekely_brs]

Nslookups completed as well.  I was using internal dns servers behind the mx as well as using google dns servers when I was directly connected to one of the mx lan ports.

[PhilipDAth]

Have you got any cellular firewall rules defined?

https://documentation.meraki.com/MX/Cellular/3G_-_4G_Cellular_Failover#Cellular_Firewall_Rules_and_B...

[dsekely_brs]

No and I have the cellular bandwidth set to unlimited.

[CptnCrnch]

Is that MX in NAT- or No-NAT mode?

[dsekely_brs]

Not sure.  I am on firmware 14.40 and don’t see that option.

[CptnCrnch]

Ok, then it‘s NAT mode, you need 15.x Beta code to disable it. In this case, my idea is unfortunately invalid.

[dsekely_brs]

@PhilipDAth Another user replied to the post below with a similar issue I am having.  I however did not have any flow preferences on any of my networks that I am experiencing this issue.  I'm just wondering if there is a setting with the S2S VPN that could be causing my issue as well.

https://community.meraki.com/t5/Security-SD-WAN/Cellular-and-VPN-in-MX/m-p/4836