Redistribute RIP routes

!Redistribution is doing where when we need to pump our routes to different protocol

!RIP redistribution is available for following protocols in Cisco IOS 15

Router(config-router)#redistribute ?
connected  Connected
eigrp      Enhanced Interior Gateway Routing Protocol (EIGRP)
metric     Metric for redistributed routes
ospf       Open Shortest Path First (OSPF)
rip        Routing Information Protocol (RIP)
static     Static routes

!RIP to EIGRP

Router(config-router)#redistribute eigrp <AS> metric <default-matric>

!RIP to OSPF
Router(config-router)#redistribute ospf <process-ID> metric <default-metric>

Network Address Translation (NAT) for IPv4 ~ Made easy

There are mainly three methods available

  1. Static NAT
  2. Dynamic NAT
  3. PAT (Port Address Translation or NAT-Overloaded)

Static NAT – one to one ip mapping

Static NAT uses a one-to-one mapping of local and global addresses. These mappings are configured by the network administrator and remain constant.

static nat config

Dynamic NAT- many to many ip mapping

Dynamic NAT uses a pool of public addresses and assigns them on a first-come, first-served basis. When an inside device requests access to an outside network, dynamic NAT assigns an available public IPv4 address from the pool.

dynamic nat config

Port Address Translation (PAT) – many(x) to many(y) ip mapping .. (x>y)

PAT (also called NAT overload) conserves addresses in the inside global address pool by allowing the router to use one inside global address for many inside local addresses. In other words, a single public IPv4 address can be used for hundreds, even thousands of internal private IPv4 addresses.

Many-to-one address mapping between local and global addresses. This method is also known as overloading (NAT overloading).

pat-config

Examples will be with next update ..!

Can't upgrade ubuntu due to low disk space on /boot (Linux)

If you get some error like this while updating Ubuntu (Linux)

The upgrade has aborted. The upgrade needs a total of 56.7 M free space on disk ‘/boot’. Please free at least an additional 3,816 k of disk space on ‘/boot’. Empty your trash and remove temporary packages of former installations using ‘sudo apt-get clean’.

Reason:

Your file system doesn’t have enough free space to install new packages of newer version to /boot partition

Solution is:

1>Run following command on terminal

dpkg -l ‘linux-*’ | sed ‘/^ii/!d;/'”$(uname -r | sed “s/\(.*\)-\([^0-9]\+\)/\1/”)”‘/d;s/^[^ ]* [^ ]* \([^ ]*\).*/\1/;/[0-9]/!d’

>>results will be like this
linux-headers-3.11.0-20
linux-headers-3.11.0-20-generic
linux-headers-3.11.0-22
linux-headers-3.11.0-22-generic
linux-headers-3.11.0-23
linux-headers-3.11.0-23-generic
linux-headers-3.11.0-24
linux-headers-3.11.0-24-generic
linux-image-3.11.0-20-generic
linux-image-3.11.0-22-generic
linux-image-3.11.0-23-generic
linux-image-3.11.0-24-generic
linux-image-3.5.0-48-generic
linux-image-extra-3.11.0-20-generic
linux-image-extra-3.11.0-22-generic
linux-image-extra-3.11.0-23-generic
linux-image-extra-3.11.0-24-generic
linux-image-extra-3.5.0-48-generic

2> Then run this command

uname -a

>>result will be

Linux user 3.11.0-26-generic #45-Ubuntu SMP Tue Jul 15 04:04:15 UTC 2014 i686 i686 i686 GNU/Linux

3> In the second step you will get kernel version currently running (3.11.0-26-generic ). Then what you should do is purge unwanted/old kernel image as follows

sudo apt-get purge linux-image-3.5.0-48-generic