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Re: IPtables bash script

Also, it seems if I only allow Related and Established on OUTPUT I
cannot access the internet, 90 percent of packets get dropped when I
try to connect to anything, but allowing new established allows
connection...but also any software would be able to call home.

On Mon, May 23, 2016 at 5:28 PM, Ralph Sanchez <rwsanchez3@gmail.com> wrote:
> Thanks for the clarification : )  And you didn't confuse the two
> explicitly, but i wasn't sure if you were advising allow NEW,RELATED/
> NEW,ESTABLISHED or ESTABLISHED,RELATED on outbound packet, but now I
> know.
> I have read through quite a few manuals and online forums, although no
> RFCs...I'm not really sure I know what they are even haha. I have
> configured myself pretty wall, editing PAM and my sysctl.conf file
> rigourously, BIOS passwording and denying USB boots without admin
> access to the BIOS, as well as other various activities including
> attempting to configure SELinux, which is nigh impossible to do it and
> have it have any effect on Jessie right now, at least as far as me and
> someone else could find.
> I have noticed that DROP on invalid first actually drops more packets
> then simply allowing Established, related...does this imply a packet
> can have more then one state??
> On Mon, May 23, 2016 at 5:20 PM, Einhard Leichtfuß <el@respiranto.de> wrote:
>> On 2016-05-23 22:32, Ralph Sanchez wrote:
>>> On Mon, May 23, 2016 at 4:13 PM,  <deb023@respiranto.de> wrote:
>>>> On 2016-05-23 19:54, Ralph Sanchez wrote:
>>>>> Yes, this is a personal laptop. If you notice, I have default POLICY
>>>>> as DROP, which means if I don't accept on ports 80 and 443 I can't
>>>>> accept HTTPS and HTTP, correct? I'm still learning how all this works,
>>>>> but that's what it seemed to me and was explained in other guides and
>>>>> tutorials I needed to do. And if I don't ACCEPT there, i dont get any
>>>>> web pages whatsoever so.
>>>> Whenever you perform an HTTP(S) request, the response should be treated
>>>> as RELATED, hence allowing all RELATED inbound traffic should suffice.
>>> So, would it be better to not based any outgoing connections of
>>> stateful connections and simply just allow it via port, since either
>>> way the port is doing to allow both wanted traffic and possible
>>> subversion, if malicious software passed the input? Or maybe put the
>>> 443 ACCEPT before the stateful filtering, and only allow established
>>> state?
>> As I said, I would simply allow all RELATED (and ESTABLISHED btw.) in-
>> and outbound connections. I might have mixed up RELATED and ESTABLISHED
>> at little in the former emails, by the way. Apart from that, you may
>> block as much as you want. And I would suggest blocking any other INPUT
>> (except for icmp (possibly partly) and lo). But again, if you really
>> want to secure your box, take the time to thoroughly read a few manuals
>> and possibly even a few RFCs.
>>>>> Thanks for the Advice on NEW, I haven't seen much said about it so
>>>>> I'll take that advice and just enable RELATED as well, considering
>>>>> that solves the biggest problem I had as far as still accessing the
>>>>> web.
>>>>> And as far as blocking outbound, I just don't see any reason to allow
>>>>> any more data in or out at any moment then is absolutely needed, and
>>>>> it should help mitigate some malicious software calling home even if
>>>>> it does get through into my system.
>>>> It could still connect via 80,443. However, you are right, your setup
>>>> will block those malicious pieces of software, that do not try to use
>>>> those (and that do not gain root rights).
>>> Yeah, i wasn't sure whether i should leave those options in or just go
>>> off stateful...see previous statement.  Also, if something gain root
>>> rights in my system, then I've got more problems then a faulty
>>> firewall.
>>>>> Thanks for the reading, that's where I'm heading now : )

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