Find Out If My DNS Server Free From DNS Cache Poisoning Bug Or Not

last updated in Categories , , , , , , , , , , , ,

How do I verify that my ISP or my own recursive resolvers are free from DNS cache poisoning bug that is promised full disclosure of the flaw by Dan on August 7 at the Black Hat conference? How do I test my dns server for DNS cache pollution or DNS Cache Poisoning bug?

Best Method To Reboot Remote Linux / Windows / UNIX Server

last updated in Categories , , , , , , , , , , , , , , ,

Q. I’ve couple of Linux / Windows server hosted in remote data center? My ISP provides following option for rebooting the box:
a) Graceful shutdown command
b) An IPMI reboot
c) A power strip

Which one is the best way to reboot server and why?
Continue reading “Best Method To Reboot Remote Linux / Windows / UNIX Server”

Linux Machine not authorized to use this PPP address error

last updated in Categories , ,

Q. I’m using Fedora Core Linux. Recently I changed my ISP. Now I get error as follows when I try to start PPP:

PPP authorization failed
Machine not authorized to use this PPP address

How do I fix this problem?
A. PPP is the protocol used for establishing internet links over dial-up modems, DSL connections, and many other types of point-to-point links. The pppd daemon works together with the kernel PPP driver to establish and maintain a PPP link with another system (called the peer) and to negotiate Internet Protocol (IP) addresses for each end of the link. Pppd can also authenticate the peer and/or supply authentication information to the peer. PPP can be used with other network protocols besides IP, but such use is becoming increasingly rare.

Auth option require the peer to authenticate itself before allowing network packets to be sent or received. This option is the default if the system has a default route.

By adding noauth option you can get rid of this problem. It means ppp do not require the peer to authenticate itself. Open /etc/ppp/options file:
# vi /etc/ppp/options
Append option:
noauth
Save and close the file. Now run ppp and you should able to connect.

Mount NFS File System Over a Slow and Busy Network

last updated in Categories , , , , , , ,

Traffic between my home and office data center encrypted using VPN but sometime my ISP get little slow or network becomes busy. I’m using Fedora Core Linux desktop system and my system freezes for a few minutes. What optimization options should be used when mounting an exported NFS share over a slow and busy network?