Sunday, April 26, 2009 

How To: Transfer your PuTTY settings between computers

Exporting Your PuTTy Configuration

Putty stores its settings in the Windows registry. To save a backup of your Putty settings, you'll need to export this registry key to a file.


(Simon Tatham is the original developer responsible for PuTTy)

1. Click Start->Run and type "RegEdt32" in the "Open" dialog. Click "Ok"

2. One RegEdt32 starts, you'll be presented with an application which looks something like:

3. Press "Ctrl+F" to bring up the Find dialog. Enter the name of the key, "SimonTratham" in the "Find What" field, and make sure only "Keys" is checked in the "Look At" section of the dialog. Finally, click "Find Next"

4. The search may take a while, reminding us that the Windows Registry is a large and mysterious place where dragons be. Let's use these few seconds to reflect on the fact that you should never, ever, never change things in the registry unless you are absolutely, positively, totally, completely, 100% dead sure that you know exactly what you're doing. When the search completes we'll see the key name for which we're looking.

5. Click File->Export. Give your file an appropriate name like, "putty.reg" and click "Save"

6. We're done! Save the putty.reg file somewhere safe. The file doesn't contain any passwords or actual SSH key values so, it's relatively safe from prying eyes. Still, it does contain your configuration and that kind of data is a private matter.

Importing Your PuTTy Configuration

To import your saved PuTTy configuration on any other Windows computer simply copy your exported registry key, right click on the file and click "Merge"

Windows will ask you for confirmation that you want to import this set of registry values. We know this file is safe, because we created it but, you should never import registry information from an unknown source.

That's all you need to know about moving your PuTTy configuration from one machine to another. This can be really useful information when upgrading to a new PC or, if you're an office IT guy where your users all have a standard list of servers they need to connect via SSH, you can create a reference configuration on once machine and "share" it between every computer in the office.


Tuesday, April 14, 2009 

ip_conntrack: table full, dropping packet.

www kernel: printk: 1 messages suppressed.
www kernel: ip_conntrack: table full, dropping packet.

Reason behind this error:

Iptables under Linux maintains a list of connections passing
through the router. Each connection tracking entry contains defined
characteristics of the packet, including the source and destination
IP address and port number. The connection tracking entries are
ultimately stored in a hash table with a fixed size. If the router
reaches the maximum number of connection tracking entries,it will
log an error:

"ip_conntrack: table full, dropping packet"

The maximum size of the connection tracking table can be increased.
The maximum size value is stored in the router's proc filesystem
in the file /proc/sys/net/ipv4/ip_conntrack_max. Increasing the
maximum size of the connection tracking table to a value larger than
the total number of connections will eliminate the error message
and prevent the router from dropping connections due to a lack of
space in the connection tracking table.

# This tell you how many sessions arte open right now.
cat /proc/net/ip_conntrack | wc -l
# This tells you the maximum number of conntrack entries you can have
in total
cat /proc/sys/net/ipv4/ip_conntrack_max

Once the previous number hits beyond the latter, you should start
seeing these messages. I would increase the latter number by calling:

echo "" > /proc/sys/net/ipv4/ip_conntrack_max

or if you want it to span reboots, you can place the following in
/etc/sysctl.conf =3D

Monday, April 13, 2009 

Install Squid on CentOS / RHEL 5

Use yum command as follows:
# yum install squid

Loading "installonlyn" plugin
Setting up Install Process
Setting up repositories
Reading repository metadata in from local files
Parsing package install arguments
Resolving Dependencies
--> Populating transaction set with selected packages. Please wait.
--> Package squid.i386 7:2.6.STABLE6-4.el5 set to be updated
--> Running transaction check

Dependencies Resolved

Package Arch Version Repository Size
squid i386 7:2.6.STABLE6-4.el5 updates 1.2 M

Transaction Summary
Install 1 Package(s)
Update 0 Package(s)
Remove 0 Package(s)

Total download size: 1.2 M
Is this ok [y/N]: y
Downloading Packages:
Running Transaction Test
Finished Transaction Test
Transaction Test Succeeded
Running Transaction
Installing: squid ######################### [1/1]

Installed: squid.i386 7:2.6.STABLE6-4.el5

Squid Basic Configuration

Squid configuration file located at /etc/squid/squid.conf. Open file using a text editor:
# vi /etc/squid/squid.conf
At least you need to define ACL (access control list) to work with squid. The defaults port is TCP 3128. Following example ACL allowing access from your local networks and Make sure you adapt to list your internal IP networks from where browsing should be allowed:
acl our_networks src
http_access allow our_networks

Save and close the file. Start squid proxy server:
# chkconfig squid on
# /etc/init.d/squid start

init_cache_dir /var/spool/squid... Starting squid: .       [  OK  ]

Verify port 3128 is open:
# netstat -tulpn | grep 3128

tcp        0      0      *                   LISTEN      20653/(squid)

Open TCP port 3128

Finally make sure iptables is allowing to access squid proxy server. Just open /etc/sysconfig/iptables file:
# vi /etc/sysconfig/iptables
Append configuration:
-A RH-Firewall-1-INPUT -m state --state NEW,ESTABLISHED,RELATED -m tcp -p tcp --dport 3128 -j ACCEPT
Restart iptables based firewall:
# /etc/init.d/iptables restart

Flushing firewall rules:                                   [  OK  ]
Setting chains to policy ACCEPT: filter [ OK ]
Unloading iptables modules: [ OK ]
Applying iptables firewall rules: [ OK ]
Loading additional iptables modules: ip_conntrack_netbios_n[ OK ]

Client configuration

Open a webbrowser > Tools > Internet option > Network settings > and setup Squid server IP address and port # 3128.

Add to Google

The Author

  • Nick Perrydoo
  • Spawn at Philippines
My profile


Read Ons

Article of the Day

This Day in History

Today's Birthday

In the News

Quotation of the Day

Word of the Day

Powered by Blogger
and Blogger Templates
© Copyright 2006 Ba-zoo-ra - All Rights Reserved.