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CGN3 modem blocking outbound ping request?

I'm a participant level 2
I'm a participant level 2

I am experiencing a problem with ping/trace route for external sites such as When trying to ping any site beyond on the Internet, none of the computers behind the modem receive a response (i.e. the ping request times out). For route tracing, the modem appears as the first hop, then it's all time outs. I have tried all of the following steps:

- Tried various computers

- Used a network connection directly from the modem

- Flushed the DNS cache

- Flushed the DHCP allocations

What makes me suspicious of the modem is that I accessed the modem management software, went to the Diagnostics tab and performed a ping and a traceroute on That worked as expected.

In summary:

- When using the modem internal diagnostics, Ping and Trace Route work perfectly

- When using a computer that goes through the modem gateway, ping and trace route requests time out

I am aware that the modem can block incoming ping requests, but I never heard of a modem blocking outgoing pings.




I'm a participant level 2
I'm a participant level 2


Ping requests are blocked by the internal modem security settings. I had it set at Medium. Changing the setting to Minimum allowed outbound pings to work again.

Honestly, it is kind of overkill to prevent ICMP to work properly in the name of security...