Connected to internet but can't open webpage unless disable firewall

Hi,

I am currently using Comodo Firewall 5.

When I try to connect to my school’s wireless network, I need to disable the firewall in order to open web sites.

I have added my school’s network as a trusted zone and use the stealth port wizard to include my school’s network zone.

When I try to open a website,
If I don’t disable the firewall, web sites will load indefinitely.
As soon as I disable the firewall, then web sites will load without any problem.

I checked the firewall events and it doesn’t show anything as being blocked.

Why is this happening? How can I fix this?

I’ve had same problem - see this link

https://forums.comodo.com/install-setup-configuration-help-cis/wireless-breakdown-following-updated-t62755.0.html;msg443382#msg443382

I’ve read this post already… unfortunately, it doesn’t resolve my problem.
My DHCP is enabled
As I mentioned, my firewall events is not showing any port or connection as blocked, so it seems that the firewall is not blocking any connection, but I still can’t connect to any websites unless I disable the firewall.

Can you show a screenshot of the firewall logs? They are under View Firewall Events.

Here is the screenshot of the firewall events, but it’s empty.

Also, I forgot to mention that I don’t experience any connect problem with my home network, I only experience the problem with my school network.

[attachment deleted by admin]

Darn. I keep forgetting that even with Global Rules set to stealth it does not log anymore by default… :o :smiley:

Try disabling Block fragmented IP Datagrams when you are in school.

It worked! I can now connect and open websites successfully at school!

Thank you!!

I just had the exact same problem on a work network - connecting to a server via an internal IP failed, via an external IP worked. Turned out to be packet fragmentation over the first route.

I’m just wondering how common this issue is ?

Maybe it should not be a default setting. Or at least be noted as a ‘first thing to try’ troubleshooting tip.