DARKCore - Ishtiaq Khan Personal Blog

Khan

The market share of 80 % or more covered by similar vendors [Networking Giants] making heavy RnS product gear for such a long time, made this field closed for innovation. However Open industry targeting inter-network products finally resulting in the form of OpenFlow or Software defined networks would be more definitive. The central idea of SDN revolves around minimizing the use of Control Plane in every switch, instead taking the Control out from every switch to the centralized ‘Controller’ responsible for making decisions, and the Switch responsible for forwarding the flow, like inter-vlan routing, ACL etc. This in turn helps in reducing the power consumption, heavy cost on switch manufacturing and making the networking products Open to small players as well i.e. start-ups from many people including Innovators. ;) However my personal take on this would be, concerning towards the security? As if the decision is not made the direct first HOP and instead via Controller what would be the impact ? the Vulnerabilities? ONE added hop in decision making? i.e. It has to go via controller but for that hopefully caching is there that should make the flow reasonably fast. But as this whole Idea is in Beta phase, and I’m hopeful that they would address all such issues and make a better solution. Though haven’t practically tested so my views are on assumptions and purely on theoretical material available to know the insight. This whole idea of making the Close Product line OPEN, I believe would not only make things better for Customers seeking a Cheap solution for RnS gear but also would give space to new/small players to jump in the industry.

There is normally too much search in looking for the Right configuration when applying the particular attribute in Router/Switch. However the Linux/Unix has their MAN pages to assist users in doing the same but with a bit of ease. Just one of my wild thoughts, how GOOD it would be to have a Manual assisting in IOS or any OS router/switch having manual inside. That’s not very un-doable, probably using some MB’s of Data in storing file, Utilizing some process cycles, but what it can help with would be amazing, having some part of complete help inside the OS would ease the configuration. - Some Vendor already have this feature.. PS: Am I been on Linux too much ? I guess yes. :)

How ping actually works… ? Layers Used are: - Application Layer—A tool that is used i.e. ‘Ping’ - Session and Transport Layer The Transport layer and Session layer functionality is used as well, this is where we expect to find facilities for reliable end-to-end data exchange, additional error checking, and the means to discriminate one program from another (using port numbers). TCP and UDP reside at this level. Than its OSI layer 3, the Network layer. This is where IP and  ICMP is, i.e. ICMP transported over IP. ICMP sends echo request and gets echo reply that is how the reachability is diagnosed, with its Codes that are well written and can be understood very easily e.g. U.U.U = A destination unreachable error PDU was received; ….. = Each period indicates the network server timed out while waiting for a reply etc etc. ICMP provides network diagnostic capabilities and feedback to those responsible for network administration and operation.  Refer RFC 792. Reference: - Knowledge Base, Cisco, RFC 729 PS: I would appreciate suggestions on this post..

Managed to unmanaged switch Trunk Scenario: L3/L2 switch(Manageable) terminating over an un-manageable switch. It will carry TWO(n) separate VLANs and now the task is to distribute the two VLANs that passes through the un-manageable switch! Establishing trunk(with TWO(or n number of)) Vlans, 1- Keep any ONE VLAN native ( for devices that does not support tagged traffic) 2- Any vlan, from L3/L2 manageable switch to the unmanageable switch ( other VLANs that u want to assign to the end host) Now the terminating PC’s NIC/OS that does not support tagged packet will go via Native VLAN defined at the trunk as native, and if you want to make some PC connected via un-manageable switch in other VLAN, you need supported NIC/OS and you’re good to go. :) This particular scenario seems to solve many hurdles when on the other end you don’t have the manageable switch or you don’t want to spend $$ :).

Its been my first from scratch Squid deploy and with the pain T-proxy.. :d I’ve looked at so many different places to grasp what it takes to master squid from zero to shiny working Squid :).. So here it is, trying to summarize as much as I can in one post.. Shiny New server with 16MB Ram- recommended for perfect squid, I had it so just the advice :) I’ve used Debian amd-64 bit, why not 32 bit ? It will crash after squid crosses 4 G Ram Cache.. :) Install simple debian, apt-get update later, than apt-get install openssh-server (for remotely managing) Get latest Kernel, mine was 2.6.35.7 Stable from kernel.org, wget URL(http://kernel.org/a-x-y.tar.bz2) check /src/usr it should be empty, now type tar -xjvf filename(linux-2.6.25.tar.bz2) -C /usr/src Now install gcc compiler and tools, apt-get install gcc Goto /src/usr/linux.x.x folder, and type linux64 and than type make menuconfig Select all the required modules u need and use help button if needed! Dont forget to select, Transparent proxy, eb tables and ip tables after that, type make clean and clean-kpkg Type in same folder, fakeroot make-kpkg –initrd –append-t-version=-ANYNAME kernel-image kernel-headers Now, dpkg -i linux-image-x.x.x.deb in /boot, type mkinitrd -o initrd.img-2.6.25 2.6.25 (mkinitrd might not work so try mkinitramfs instead or update-initramfs -k img.x.x -c) Goto /boot/grub/menu.lst and add the installed kernel or just type update-grub to automatically load the modofications :) Now your kernel is compiled next is, Bridge tables, IP tables and Squid Configuration.. Install IPables and tar it and install in the folder–>configure–>make and I would prefer get checkinstall package as it makes it easier to remove the package later(as it creates .deb) Download and install ebtables similar to step 1 Configure IP tables as per your requirements Make partitions as per your requirements, install parted ( for partprobe without restarting applying fdisk changes ) Get reiserfsprog for making reiserfs partition. In my case 3 partitions, 1 Reiserfs and 2 ext2 partitions Than create folders in /usr/local/squid/var/cache/sdX Modify /etc/fstab for the partitions e.g. /dev/sdaX  /usr/local/squid/var/cache/sdaX reiserfs defaults,notail,noatime 1 2 ( or for ext2 defaults,noatime 1 2) Download and place storeurl.pl in /usr/local/squid, with chmod 700 storeurl.pl (executable) Modify /usr/local/squid/etc/squid.conf as per your requirements Run /usr/local/squid/sbin/squid -z (creating swap directories, make sure you set the cache directories ownership to, chown nobody:nogroup * ) Then finally /usr/local/squid/sbin/squid start ( If everything worked fine, you are good to go) Will keep updating how to TShoot it and about its Addons, but what I’ve seen that Squid is one very touchy server :) Gud luck!

I’ve been working on freeNAS for sometime now, its one good network resource(HD) sharing OS. (freebsd+freenas) Works best if someone wants to create a multimedia server accessed via Network(I’ve been dealing with 15-16K Customers) and working fine ! So, lets start with basics, which I had to look different places for.. :) 1- Installation is pretty easy, so skipping this part ( You need Front Webpage to provide services. ftp links to hard drive partitions etc) 2- Access Console, set interface IP, Gateway(if required), to access the freeNAS via WEB 3- Default uid/pass= freenas/freenas for webGUI 4- Management of Harddrives(Storage), Easiest is, Mount haddrive—Format has to be UFS (if not UFS it will format and convert it to UFS :). 5- Under Shares-Select the folder you want users to access. 6- Check if you need static routes- May not be required depending on your requirements 7- Multiple other features, and i would say extremely easy to manage and use Any addition will be welcomed.. :)

PS: These are scratchy notes, hard to understand may be.. : ) Will update this post by adding the Image of a sample Dialup Network.