Security Basics mailing list archives
Re: N00b Question
From: josh <josh.reynolds () tstc edu>
Date: Wed, 5 Jan 2005 16:58:16 -0600
There is a great product called packet shaper by packetteer. This device blocks traffic at the application level. If a user tries to use gnutella, AIM, iTunes, etc... on a different ports or IP's other that the standard ports and IP's this device will detect it. This device detects the signatures of these application's packets as they pass through this device. I work of a college and as you can imagen our students ate up our bandwidth with P2P apps, we purchased this device and saved a whole lot of bandwidth. I hope this helps. On Wednesday 05 January 2005 15:00, Scott Ladd wrote:
The method you mention has man flaws, namely, multiple hosts. AIM for instance, uses multiple IP address and ports for connecting. You would have to block an IP Range for that matter. Setting up a firewall is your best bet in the end. -SL -----Original Message----- From: Beauford, Jason [mailto:jbeauford () EightInOnePet com] Sent: Monday, January 03, 2005 8:30 AM To: security-basics () lists securityfocus com Subject: RE: N00b Question No need to sit there and block ports. Just block access to the hosts these services connect to. For instance I-Tunes: I-Tunes has built in Internet Radio which can suck up my bandwidth. I use Websense to block HTTP and other ports. However, I-Tunes uses a HUGE range of ports. Sure you can block all of those ports, but it's just much easier to block the site from which I-Tunes gathers it's XML list of Radio stations. Now the proggie just errors out. MSN and Yahoo Chat all connect to some remote host. Install and fire up Ethereal on your PC, Install these programs and sign in. Check your Ethereal Logs and you'll easily be able to identify which hosts those programs are connecting to. My $.02. Happy New Year All! JMB -----Original Message----- From: G.Crow [mailto:secure.computing () gmail com] Sent: Thursday, December 30, 2004 10:33 PM To: security-basics () lists securityfocus com Subject: RE: N00b Question For blocking certain sites your best bet is a proxy of some sort, presumably transparent. Lots of people on this list will point you towards Squid if you're looking in the open-source realm. You *could* block site IPs in your firewalls (PIX firewalls are almost all, if not all, in the 500-scheme. I haven't looked at the lineup recently.) That is, however, not a great solution for a variety of reasons. If you are blocking the web-based email, why do you need to block the ability to upload attachments? For MSN/yahoo chat you can block the ports in your external firewall. This will stop 95% of your users (possibly more if MSN/yahoo don't accept connections on any port like AIM does.) You can also see if your infrastructure supports deep packet inspection - Cisco has a good variety of capabilities regarding that, but I can't for the life of me remember the acronym, and my Cisco books are in the office. I avoid it, myself, since it punts packets to the processor, but that doesn't matter as much with a slower external link. Quotas established for web surfing? Do you mean accounting per computer (he's been on the web *this* much today) or do you actually mean cutting it off after a certain point per day? Logging and log analysis is easy enough, but true quotas would require authentication of some sort most likely, and are probably more trouble then they're worth. If bandwidth is an issue I would just implement QoS and put port 80/443 traffic in a low CoS. Gabe-----Original Message----- From: Harshal Dedhia [mailto:harshal.dedhia () skybird-travel com] Sent: December 30, 2004 11:42 AM To: security-basics () securityfocus com Subject: N00b Question Hi, I am very new to the firewall and network security world. I have a situation wherein I need to block webbased email access and the ability to upload attachments to web-based email. I also need to ensure that MSN/yahoo chat is disabled and quotas are established for web surfing. Is there an Open Source solution to this problem. The network comprises Cisco Routers and 500 series firewalls. Cheers! Harshal
-- Josh Reynolds Network Manager Texas State Technical College - Waco 1-254-867-3375 "This e-mail may contain the thoughts and opinions of Josh Reynolds and may not represent official Texas State Technical College Waco policy."
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Current thread:
- RE: N00b Question Beauford, Jason (Jan 05)
- <Possible follow-ups>
- Re: N00b Question jayson . agagnier (Jan 05)
- RE: N00b Question Scott Ladd (Jan 05)
- Re: N00b Question josh (Jan 05)
- Re: N00b Question Mike (Jan 06)
- Re: N00b Question josh (Jan 05)
- RE: N00b Question Beauford, Jason (Jan 05)
- RE: N00b Question Corbett, Tim D. (James Tower) (Jan 06)
- RE: N00b Question David Gillett (Jan 07)