Re: Firewall Blocking More Websites

From: Ben Measures (saint_abroadremove_at_removehotmail.com)
Date: 01/30/04 

Date: Fri, 30 Jan 2004 02:43:44 +0000

Chris McHugh wrote:
> Hi All,
>
> I am running Mandrake 9.1 with Firestarter 0.9.1. This box connects to a
> router out to the rest of the world. I have noticed that over the last ~4
> months that more webites will not load with Mozila because they are
> getting block by firewall. They are trying to connect on various ports
> (55643, 55642, 5373, etc.). It used to be that only "bad" sites (take a
> guess) would try these ports, but it seems that many, including legit
> commerical sites like Nikon and Opensource sites are also getting blocked.
> It is getting to be a PITA. I can allow access per site w/ Firestarter
> (which just creates rules for iptables) but that is a messy solution.
> Anyone elese notice the increase lately? Any thoughts or ideas?
>
> Thanks,
>
> Chris

> It used to be that only "bad" sites (take a guess) would try these
> ports

I would like to see your source for that information. It seems highly
suspicious to me (FUD).

> it seems that many, including legit commerical sites like Nikon and
> Opensource sites are also getting blocked.

According to internet specs, ports 10000+ are client ports. Http
specification describes the client requesting information from http
server at port 80, and then the http server sending the information to
the client on any of the client ports (ie ports > 10000).

If you block client ports then some (http) responses won't get back to
you (usually random).

Or as nikkon said,
> Initial http connections with a site occur on (default) port 80. The return
> data stream(s) can occur on any number of local ephemeral ports for text,
> images, shockwave flash animations, and the like.
>
> Nikon opened about a half dozen ports for data transfers of various kinds,
> as seen by iftop.
>
>
> tony 

-- 
Ben M.
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