RTBH stands for Remote Triggering Black Hole, which means, the ability to route traffic to black hole from remote. In the real world the intention is to allow customers to instruct their ISP to route traffic to black hole without any intervention from the ISP side.
So why do we want to route traffic to black hole? in case of DoS/DDoS we would like to stop the attack ASAP and the best way to accomplish that is by routing traffic designate to victim into black hole and to prevent from the excess traffic (or pps) to reach or go through our links and devices.
looking on the network diagram we can see that the attacker will conduct his DoS attack through the ISP toward the customer server.
The customer can stop the attack by advertising the victim IP (destination) to the ISP with special community where as the ISP in return will re-route the traffic to this IP toward black hole (null 0 or discard).
Currently we are working with Level3 and Tinet which support RTBH communities 3356:9999 and 3257:2666 respectively.
So if the victim IP was 200.10.0.1 the configuration for Level3 will be:
ip prefix-list PL_RTBH_LEVEL3 permit 200.10.0.1/32
!
route-map RM_BGP_LEVEL3_OUTBOUND permit 10
match ip address prefix-list PL_RTBH_LEVEL3
set community 3356:9999
take note that although ISP's doesn't s support BGP advertisements less the prefix /24 when it comes to RTBH you can advertise any prefix length includes /32.
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Tuesday, May 22, 2012
Sunday, May 20, 2012
How to reset Safe@Office appliance to factory default
Few things to know before reset to factory default:
1.
All configurations will be
erased!
2.
The appliance will revert
back to the firmware version which he came from the manufacture, hence all
firmware upgrades, which has been done in the past, will be loss.
3.
You should follow the
instructions carefully to avoid permanent damage to the appliance.
I found that there are two ways to reset Safe@Office
appliance, to factory default, and I think it somehow depends on the firmware
version which has been installed on the factory.
Method #1:
1.
Make sure the Safe@Office
appliance is powered on
2.
Press the RESET button on
the back of the Safe@Office appliance steadily for seven seconds and then
release it.
3.
Allow the Safe@Office
appliance to boot-up until the system is ready (PWR/SEC LED flashes slowly or
illuminates steadily in green light).
4.
Connect a PC to the
appliance and check that you receive 192.168.10.xxx IP address
5.
Login to http://my.firewall (not to 192.168.10.1) and
enter password for admin access.
Method #2:
1.
Unplug the power cord.
2.
Hold the reset button on
the back of the appliance
3.
Plug in the power cord
while holding the button until the PWR/SEC LED is steady red.
4.
Leave the reset button for
3 seconds
5.
Press the reset button
again for 10 seconds until the PWR/SEC LED starts blinking red
6.
Connect a PC to the
appliance and check that you receive 192.168.10.xxx IP address
7.
Login to http://my.firewall (not to 192.168.10.1) and
enter password for admin access.
Warning: If you choose to reset the Safe@Office appliance by
disconnecting the power cable and then reconnecting it, be sure to leave the Safe@Office appliance disconnected for at least three seconds, or the Safe@Office appliance might not function properly until you reboot it as
described below
Sunday, May 13, 2012
How to upgrade Juniper EX4200 switch software
1. Format DOK (disk-on-key), with enough space, to FAT32
2. Copy the software image (jinstall-ex-4200-11.3R2.4-domestic-signed.tgz) into the DOK
3. Plug the DOK into the USB port of the switch in the backside
4. Enter shell mode [you will need root password]
user@switch> start shell
% su
Password:
root@switch%
|
5. Mount the DOK
mount_msdosfs
/dev/da1s1 /mnt
|
6. Copy the image file to
temporary directory
cp /mnt/
jinstall-ex-4200-11.3R2.4-domestic-signed.tgz /var/tmp
|
7. Return to operational mode
cli
|
8. Start upgrade process
request
system software add /var/tmp/ jinstall-ex-4200-11.3R2.4-domestic-signed.tgz
|
How to enable Windows XP Network Level Authentication
In order to allow Windows XP to connect, using RDP, to
Windows 7, without changing security level, we need to accomplish two steps:
1.
Install Microsoft Remote
Desktop Connection 7.0 client or later
2.
Tweak some registry values
Follow these steps to make the required registry tweaks:
1.
Open the registry editor,
Start->Run->regedit
2.
Go to HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Lsa
3.
Modify the value Security
Packages
4.
Add the value tspkg
5.
Go to HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\SecurityProviders
6.
Modify the value
SecurityProviders
7.
Add the value credssp.dll
(don’t forget the comma before)
8.
Exit registry editor
9.
Restart the computer
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