Hi,
Is there such thing as a default block list?

We use RB33's, 100's of them. They provide a cellular connection to the web for an RPI which collects sensor data.

I have around 10 or so that have stopped sending data via the RPI. We use a std build on everything, all RB have the same FW so i am confident its not a settings thing. Only thing i can think of is the RB is blocking outbound data somehow or maybe the RPI but i have no idea how.

I know there is data to send as my RPI go into backup mode if they can not connect to the server so i can see it all stored up ready to send. My servers are working fine as i have around another 150 odd sensors all communicating.

Remote access to the RBs is fine and they are quick so do not have signal issues so cant think of any other reason why the data can not be sent

Quick update... after some further investigation it seems that data is being sent when its an initial connection as we just sent a small packet to check the server is available.If we get back an "OK" the RPI then uploads a larger amount of data, around 100kb.. that's what is being blocked.

So single packet is OK.. we we know the RB and RPi is communicating with the server.. larger data uploads are being blocked.

is the RB capable of doing that, if not i can concentrate more on the RPI.

If the initial packet goes through, you should look into the receiving end IMHO.

Unless you have some on RB firewall rules with dynamic timestamp based address list which are used for blocking after x occurences ?
But you should see that in your config.

Maybe check the MTU if small packets can be sent through, but large amount of data can't? Most cellular connections that I have used have MTU smaller than 1500.

Maybe check the MTU if small packets can be sent through, but large amount of data can't? Most cellular connections that I have used have MTU smaller than 1500.

Really helpful thanks. I have gone back to our provider and asked them to confirm the MTU size. We have a private Subnet with a single dedicated internet breakout. They have already checked throughput and confirmed we are not being throttled so the MTU could be a thing. Thanks