iptables

Obie · 08-18-2004, 12:15 AM

/bin/bash,

That makes sense now. Do i have to run iptables-save everytime I make a change?

Obie · 08-18-2004, 12:23 AM

A couple of queries,

If I use my linux PC as my firewall, is there a way block say for example Internet Explorer from a Windows PC from accessing the Internet and only allowing say Mozilla. I did ask this question some while ago but didn't get an approriate reply.

barisdemiray · 08-18-2004, 08:37 AM

Quote:

Originally posted by Obie
A couple of queries,

If I use my linux PC as my firewall, is there a way block say for example Internet Explorer from a Windows PC from accessing the Internet and only allowing say Mozilla. I did ask this question some while ago but didn't get an approriate reply.

I think you can't. Because iptables works at layer 3 and 4, and there is no application-specific traffic (even http) only ports, addresses.. Also you can't distinguish the traffic that comes from Mozilla or IE, because there are standarts for http. But you can remove IE from the computer simply ;-) Because IE is a browser(-like software) and if it will not be able to connect web site; then we don't need it..

Obie · 08-18-2004, 04:32 PM

barisdemiray,

Thanks. Is it not possible to block request headers via iptables? I suppose if it possible how do I go about looking for specific request headers for specific software. I rather not uninstall any software because it can simply be re-installed. That beats the purpose. I rather just block it.

/bin/bash · 08-18-2004, 08:30 PM

Quote:

Originally posted by Obie
/bin/bash,

That makes sense now. Do i have to run iptables-save everytime I make a change?

Yes if you make a change and you want to keep it you would have to run iptables-save. Of course you should make a backup of /etc/sysconfig/iptables before you do that just to be safe.

Obie · 08-19-2004, 08:00 PM

/bin/bash,

Thank you.

barisdemiray · 08-20-2004, 03:49 AM

Quote:

Originally posted by Obie
barisdemiray,

Thanks. Is it not possible to block request headers via iptables? I suppose if it possible how do I go about looking for specific request headers for specific software. I rather not uninstall any software because it can simply be re-installed. That beats the purpose. I rather just block it.

Application specific request headers are only packet payloads in the layers which iptables works. I'm not sure whether it could be but there is a netfilter match extension that make you be able to match a string (extension's name is also String) with the packet data. Look at the link below

http://www.netfilter.org/documentati...-3.html#ss3.18

If you write the results and details like request header diff.s between browsers after your work i would be happy. Hope these helps.