HomeLab: Simple DHCP Service Configuration on a Cisco Router

Cartoon-golfer-009Sometimes when I learn something new in the world of technology, I am often amazed that something that I assumed was technically advanced is rather quite simple.

Such is the case with configuring DHCP on a Cisco Router. I mean, is it just me or do network guys sometimes act as if everything that they do is takes elite technical skills and tons of experience. Don’t get me wrong, I know that networking is not exactly easy. But can we just agree to admit that once in a while some things are easier done than said. Anyway, for me this was the case with configuring a DHCP pool on a Cisco Router.

In this instance I was working on getting a new virtual machine up and running on my ESXi host. This particular appliance needed to boot via dhcp so you could access its web interface. So I jumped on my 2621xm and created the pool.

First we enable the dhcp service

r-2621-1(config)#service dhcp

Then we create a pool

r-2621-1(config)#ip dhcp pool LabPool
r-2621-1(dhcp-config)#network 10.2.0.1 255.255.255.0

Next we set a few bits and bobbles so that clients can route.

r-2621-1(dhcp-config)#dns-server 10.2.0.71
r-2621-1(dhcp-config)#default-router 10.2.0.1
r-2621-1(dhcp-config)#domain-name localdomain

In this case I wanted to exclude a bunch of ips from the range

r-2621-1(dhcp-config)#ip dhcp excluded-address 10.2.0.1 10.2.0.100

Now save your config with copy run start.

The command below shows me all my dhcp clients

r-2621-1#show ip dhcp binding
Bindings from all pools not associated with VRF:
IP address          Client-ID/              Lease expiration        Type
Hardware address/
User name
10.2.0.101          0050.569a.7dbe          Oct 16 2013 11:21 PM    Automatic

This handy command shows me information pertaining to my pool

r-2621-1#show ip dhcp pool

Pool LabPool :
Utilization mark (high/low)    : 100 / 0
Subnet size (first/next)       : 0 / 0
Total addresses                : 254
Leased addresses               : 1
Pending event                  : none
1 subnet is currently in the pool :
Current index        IP address range                    Leased addresses
10.2.0.102           10.2.0.1         – 10.2.0.254        1
r-2621-1#show ip dhcp conflict

Related articles

HomeLab: Simple Cisco EIGRP Setup
Cisco DHCP Client Lease Time
HomeLab: Simple SSH Setup on a Cisco Router
HomeLab: Cisco 2621 Router Password Recovery/Factory Reset
Configuring InterVLAN Routing on a Layer 3 Switch and providing DHCP to multiple subnets Part 1

HomeLab: Upgrading Cisco IOS Via tftp on RHEL

0012fbf7_mediumSo I was planning on blogging about this process simply because I keep forgetting it. Being that I am in the middle of building out my lab, and have a ton of old cisco hardware with ancient images, I have found myself going through the process of updating firmware quite a bit as I tinker with different IOS images.

The first thing that you are going to need is a tftp server, which I am running on my Fedora 18 desktop. Its a very easy setup, and has been simply documented on the link below. Note the article below is specfically about how to setup a tftp server on RHEL, however the process is pretty much the same.

How to Install a tftp Server on RHEL

Now if you are looking to setup a tftp server on Windows, well I cannot help you there. If I recall you just download and install a server app, and away you go.

Below is another link that I have found that also does a fine job of explaining the Cisco side of the process simply, without getting too technical and long winded.

How to Upgrade Cisco IOS Images

 

Related articles

HomeLab: The Cisco 3560G
HomeLab: Configuring the NTP Client on a Cisco Catalyst Switches
Configuring TFTP in Linux
Best Cisco IOS switch for home use
Cisco IOS: Basic Configuration of a Switch.
Cisco IOS : How to configure passwords.

RHEL6 – How to Setup an Anonymous Download Only FTP Server

Sticker,375x360A while back I spit out a post on how to configure an anonymous ftp server that allowed uploads and downloads, which you can find here.

Its a very exciting read and will tell you everything that you need to know to get you up and running with an anonymous ftp server. However those instructions are specifically for a server that allows anonymous uploads as well as downloads. So today we are going to go over only the steps for anonymous download, which is actually much easier.

Basic Install & Configuration

So first lets install vsftp.

# yum -y install vsftpd && service vsftpd start && chkconfig vsftpd on

Then edit /etc/vsftp/vsftpd.conf and make sure that the following line is uncommented.

anonymous_enable=YES

You should also be aware of the following configuration directive. By setting local enable to no in /etc/vsftp/vsftpd.conf, you disallow local Unix users access to ftp, which ensures that your ftp server is truly anonymous only.

local_enable=no

Now restart vsftpd and you should be in business

Testing Anonymous Download

To test ftp you need an ftp client, which can be installed via yum as seen below.

yum -y install ftp

Then you should be able to ftp to localhost like as seen below and get a file. Note that an anonymous login does not a password

# ftp localhost
Trying 127.0.0.1…
Connected to localhost (127.0.0.1).
220 (vsFTPd 2.2.2)
Name (localhost:root): anonymous
331 Please specify the password.
Password:
230 Login successful.
Remote system type is UNIX.
Using binary mode to transfer files.
ftp> ls
227 Entering Passive Mode (127,0,0,1,170,125).
150 Here comes the directory listing.
drwxr-xr-x    2 0        0            4096 Aug 30 15:37 pub
-rw-r–r–    1 0        0               0 Aug 30 15:39 test2
-rw-r–r–    1 0        0               0 Aug 30 15:38 testfile
226 Directory send OK.
ftp> get test2

The same test executed as root ( a local user) should fail as seen below.

# ftp localhost
Trying 127.0.0.1…
Connected to localhost (127.0.0.1).
220 (vsFTPd 2.2.2)
Name (localhost:root): root
530 This FTP server is anonymous only.
Login failed.
ftp>

Unix File Permissions and SELinux

One of the things that can ruin your day when it comes to getting and ftp server up and running is SELinux. However when setting up an anonymous download ftp server using the default ftp root directory you don’t actually need to change anything.

By default your ftp root directory is going to be /var/ftp/, and its SELinux context and default perms are going to be as seen below.

drwxr-xr-x. root root system_u:object_r:public_content_t:s0 /var/ftp

Here the default context is public_content_t which by allows reads but not writes, and the default Unix perms allow reads and not writes.

Changing Default FTP Root Directory

If you wanted to change anonymous vsftp to use a different root directory (other than /var/ftp) you would need to add the following line to /etc/vsftpd/vsftpd.conf. In the example below I am setting my new ftp root to /shared/ftp

anon_root=/shared/ftp

You are also going to need to asign the correct SELinux file context (public_content_t) to your new directory.

# semanage fcontext -a -t public_content_t “/shared/ftp(/.*)?”

# restorecon -vvFR /shared/ftp

Configuration Differences Between Anon Upload and Download

So as I stated above its actually a bit easier to configure an anonymous download only ftp server, than it is to configure it to allow uploads as well.  This section for reference only, my post on configuring anonymous upload and download ftp server can be reference here.

First you will need to assign a different SELinux context. Its public_content_rw_t not public_content_t.

# semanage fcontext -a -t public_content_rw_t ‘/var/ftp(/.*)’

# restorecon -vvFR /var/ftp

You will also need to fiddle with SELinux booleans

# setsebool -P allow_ftpd_anon_write=1

And we are also going to want to change the Unix permissions on our ftp root directory. Here we are changing group ownership to ftp and setting the setgid bit.

# chgrp ftp /var/ftp/
# chmod 2760 /var/ftp

Good luck and try not to break anything.

RHEL6 – How To Configure an NFS Server

Waffle1 Do you know whats almost as delicious as a tasty waffle with pure AAA Vermont maple syrup smothered all over it. Neither do I.

However I did run across a very well written blog post on how to configure an NFS server on RHEL6.

Wierd, is it a NFS server or an NFS server, the latter sounds and looks better but i dont think its correct.

Anyway link below:

http://aaronwalrath.wordpress.com/2011/03/18/configure-nfs-server-v3-and-v4-on-scientific-linux-6-and-red-hat-enterprise-linux-rhel-6/

Latest HP Proliant SmartStart and Firmware DVDs 10-06-2010

 

Hpweb_1-2_topnav_hp_logo

If you are having issues with your HP server and were thinking about calling support, you might as well put down the phone. Seems to me that their default first step of troubleshooting is to advise you to upgrade to the latest firmware.

According to HP support these were both release just a couple of days ago. Links are below. Firmware DVD is just that, firmware. Smart Start is drivers and diagnostics.

 

Firmware DVD

Smart Start DVD