We are having an issue with our internet connection and I cannot seem to identify what specifically is causing the issue.
Throughout the day, certain sites suddenly drop all for about 2 minutes returning an error of "ERR_CONNECTION_REFUSED" but I am having trouble identifying what part of the chain is refusing the connection.
When the issue occurs, the affected sites continue to respond to ping requests, so it isn't a connection issue. It only affects certain websites too. Sometimes our banking institutions site goes down, but Google remains up. We check other sites and Facebook remains online but Microsoft sites go down so Outlook dies for a short period.
And it isn't limited to a single device within the office, it is multiple at once.
We have two theories but have no solid idea how to seperate the two. One is that our ISP is dropping the ball somewhere and by the time we get someone to look into it... there is no issue and they close the ticket. The other is that our simple site firewall is somehow causing an issue but nothing appears to be in the logs indicating an issue.
Is there a way to see where the "refusal" is actually originating? If the firewall is somehow refusing it, is there something in the RST packet that would indicate as such? If the ISP is having connectivity issues to certain services periodically, can I identify what part of their system is causing the refusal to connect??
Is there any point in installing Wireshark and getting a constant flow and hoping something indicates a problem? I assume I would only be looking at port 443 because ICMP work fine...
