LAN cannot access Internet

[pfguy]

ok i have my pfsense box up and running fine for about 1 month but few days ago LAN cannot access internet. By saying that i mean users open a browser, type in a URL and it returns "safari cannot get xxx because cannot reach the server"
I have turn off captive portal.
strange enough, i can ping the website and get replies, no problem.
i can also do nslookup and get replies, no problem neither.

:-
anyone having this issue?

[firewalluser]

Do you log your fw rules and then see whats getting through and whats being blocked in the fw logs?

[pfguy]

nothing strange in the logs..
now i have some update:
changed to another PC running 2 Realtek NICs.. restore with the old config. EVerything back up running just fine !
the old PC has 1 onboard Intel NIC and 1 Realtek NIC. It had some problems like this in the past too. So i think it could be the compatibility issues with the different NICs here.

[viragomann]

In the docs you find some points that should be checked in that case:
https://doc.pfsense.org/index.php/Unable_to_Access_Some_Websites

If the Router is connected to the ISP there's often an adjustment of the interfaces MTU required.