[CentOS] CentOS automatically blocks port 80 out-of-the-box

Michael A. Peters mpeters at mac.com
Wed Apr 8 00:49:45 UTC 2009

David M Lemcoe Jr. wrote:
> Maybe I just haven't installed enough distros, but the times I've installed CentOS, I've had to remember that by default, iptables is blocking inbound port 80 requests. This leads me to believe that I have a non-OS firewall error because I can ping but not http request. 
> Is there a particular reason for this? Or is it a fail on my end?

Very few ports are open out of the box.
I'm not sure, but I think if you choose the webserver (or is it server 
??) option at install it might have port 80 open.

Port 22 is open for ssh. I think 631 (cups) is as well, but not positive.

You can configure the firewall with system-config-securitylevel-tui 
after install (it runs during firstboot as well) where you can easily 
tell it to turn on port 80 (and/or 443) for web services.

pinging a box has nothing to do with ports are blocked, open, or closed.
You can filter pings but I don't believe the firewall does by default.

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