Easy, show them RFC 3514 and let them know you would need a firewall to block the "Evil" bit...cash, check or charge?
-----Original Message----- From: Priscilla Oppenheimer [mailto:[EMAIL PROTECTED] Sent: Thursday, April 03, 2003 11:46 AM To: [EMAIL PROTECTED] Subject: RE: hacking challenge [7:66720] Wilmes, Rusty wrote: > > this is a general question for the security specialists. > > Im trying to convince a client that they need a firewall.... > > so hypothetically, > > if you had telnet via the internet open to a router (with an > access list > that allowed smtp and telnet) (assuming you didn't know the > telnet password > or the enable password)that had a bunch of nt servers on > another interface, Do you actually mean that you are allowing Telnet and SMTP to go through the router? You said "to" above which is confusing. Allowing Telnet to the router unrestricted would be a horrible security hole, even for people who don't know the password because passwords are often guessable. But I don't think that's what you meant... Allowing Telnet and SMTP through the router is more common, especially SMTP. You have to allow SMTP if you have an e-mail server that gets mail from the outside world. Avoid Telnet, though, if you can. It sends all text as clear text, including passwords. The question is really how vulnerable is the operating system that the SMTP server is running on? It's probably horribly vulnerable if your client hasn't kept up with the latest patches, and it sounds like your client is the type that hasn't? In fact, the server is probably busy attacking the rest of us right now! ;-0 So, as far as convicing your customer.... The best way may be to put a free firewall, like Zone Alarm, on the decision maker's computer and show her/him all the attacks happening all the time. Or if she already has a firewall, walk her through the log. Good luck. I have a good book to recommend on this topic: Greenberg, Eric. "Mission-Critical Security Planner." New York, New York, Wiley Publishing, Inc., 2003. Here's an Amazon link: http://www.amazon.com/exec/obidos/ASIN/0471211656/opendoornetwinc/104-99 01005-4572707 Priscilla > how long would it take a determined hacker a) cause some kind > of network > downtime and b) to map a network drive to a share on a file > server over the > internet. > > Thanks, > Rusty > > > -----Original Message----- > > From: Larry Letterman [mailto:[EMAIL PROTECTED] > > Sent: Wednesday, April 02, 2003 1:44 PM > > To: [EMAIL PROTECTED] > > Subject: RE: VLAN loop problem [7:66656] > > > > > > Yes, > > it prevents loops in spanning tree on layer 2 switches from > > causing a loop > > by disabling the port on a cisco switch... > > > > > > Larry Letterman > > Network Engineer > > Cisco Systems > > > > > > > > > > > > > -----Original Message----- > > > From: [EMAIL PROTECTED] > > [mailto:[EMAIL PROTECTED] Behalf Of > > > Thomas N. > > > Sent: Wednesday, April 02, 2003 12:18 PM > > > To: [EMAIL PROTECTED] > > > Subject: Re: VLAN loop problem [7:66656] > > > > > > > > > What does "portfast bpdu-guard" do? Does it prevent > interfaces with > > > portfast enabled from causing the loop in my scenario? > > > > > > > > > ""Larry Letterman"" wrote in message > > > news:[EMAIL PROTECTED] > > > > > > > port mac address security might work, altho its a lot of > admin > > > > overhead..are you running portfast bpdu-guard on the > access ports? > > > > > > > > > > > > Larry Letterman > > > > Network Engineer > > > > Cisco Systems > > > > > > > > > > > > ----- Original Message ----- > > > > From: Thomas N. > > > > To: [EMAIL PROTECTED] > > > > Sent: Tuesday, April 01, 2003 8:14 PM > > > > Subject: VLAN loop problem [7:66656] > > > > > > > > > > > > Hi All, > > > > > > > > I got a problem in the production campus LAN here > between > > > VLANs. Please > > > > help me out! Below is the scenario: > > > > > > > > We have VLAN 10 (10.10.x.x) and VLAN 20 (10.20.x.x) > subnets. > > > Routing is > > > > enable/allowed between the two subnets using MSFC of > > the 6500. Each > > > subnet > > > > has a DHCP server to assign IP address to devices on > its subnet. > > > > Spanning-tree is enable; however, portfast is turned on > on all > > > > non-trunking/uplink ports. Recently, devices on VLAN > 10 got > > > assigned an > > > IP > > > > address of 10.20.x.x , which is from the DHCP on the > > other scope and > > > also > > > > from 10.10.x.x scope, and vice versa. It seems that we > a > > > loop somewhere > > > > between the 2 subnets but we don't know where. I > > noticed lots of end > > > users > > > > have a little unmanged hub/switch hang off the network > > jacks in their > > > > cubicals and potentially cause loop. > > > > > > > > Is there any way that we can block the loop on the > > Cisco switches > > > without > > > > visiting cubicals taking those little umanaged > > hubs/switches? Thanks! > > > > > > > > Thomas Message Posted at: http://www.groupstudy.com/form/read.php?f=7&i=66770&t=66720 -------------------------------------------------- FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
