blocking only https access

blocking only https access

[Leonardo Carneiro]

Hi everyone,

I have blocked outgoing connections using port 443 in my network to 
force everyone to use the webproxy. However, some non-http applications 
(like ShowMyPC) uses the port 443, and don't support proxies yet. I've 
contacted the support of the software to know with IPs do i have to 
allow it to make the program work properly, but they said there change 
their server IPs very often, so they recomend use the domain name to block.

I have readed a lot here in the list and in other places that i SHOULD 
NOT use domain names in iptables, cause it will result in a dns request 
to every packet that reachs that rule.

the question is: is there a way that i can identify only SSL packets 
that contain web content, so i can allow those who haven't, like the 
ShowMyPc packets?


-- 

*Leonardo de Souza Carneiro*
*Veltrac - Tecnologia em Logística.*
lscarneiro@veltrac.com.br <mailto:lscarneiro@veltrac.com.br>
http://www.veltrac.com.br <http://www.veltrac.com.br/>
/Fone Com.: (43)2105-5601/
/Av. Higienópolis 1601 Ed. Eurocenter Sl. 803/
/Londrina- PR/
/Cep: 86015-010/

	

Re: blocking only https access

[Marek Kierdelewicz]

>Hi everyone,

Hi,

>I have readed a lot here in the list and in other places that i SHOULD 
>NOT use domain names in iptables, cause it will result in a dns
>request to every packet that reachs that rule.

Not really. Domainname is resolved at the time of rule addition to a
ruleset. Netfilter stores the destination address in numerical form.

You can use CRON to restart firewall every night or even every hour.
This would allow you to have the current server addresses in a
ruleset.

Cheers,
Marek Kierdelewicz

Re: blocking only https access

[Leonardo Carneiro]

Marek Kierdelewicz escreveu:
>> Hi everyone,
>>     
>
> Hi,
>
>   
>> I have readed a lot here in the list and in other places that i SHOULD 
>> NOT use domain names in iptables, cause it will result in a dns
>> request to every packet that reachs that rule.
>>     
>
> Not really. Domainname is resolved at the time of rule addition to a
> ruleset. Netfilter stores the destination address in numerical form.
>
> You can use CRON to restart firewall every night or even every hour.
> This would allow you to have the current server addresses in a
> ruleset.
>
>   
Ok, tks Marek. I'll try this.

> Cheers,
> Marek Kierdelewicz
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