Wednesday, December 23, 2009

Fix for re-imaging Lenovo X61t laptops


Problem:

Re-imaging using Clonezilla and rebooting a Lenovo X61t laptop threw up the error "Signature Failure"

Solution:
Quoting from http://www.ecs.umass.edu/pipermail/umasslug/2008-August/003380.html
However:  I did get the idea from various 
websites that it seemed to be an issue with the MBR, so I started
playing with options in Clonezilla. It turns out that if I de-select
the -g auto and -r options, and select -t1, the system works. I've just
confirmed on two of the broken systems, so it looks like it's going to
be a consistent fix.

It looks like this is a common issue on the Lenovo laptops, so I'm
glad to have found a solution. (Also, I've got six more to image today,
and possibly more next week...)
That worked.  It appears that -t1 replaces the MBR with the pre-made syslinux MBR.a

Wednesday, September 23, 2009

Registry Permissions resetting

Ok ... I could have used this recently as we migrated from an samba based domain to an AD domain.  The quickest way to migrate 20+ users was to just add the new domain user to the local admin group and then repoint their Docs and Settings folder to their old folder.

Using this subinacl tool (http://www.winhelponline.com/blog/reset-the-registry-and-the-file-permissions-in-windows-xp) might have made the process both easier and more secure.

Read up on Subinacl at http://www.microsoft.com/downloads/details.aspx?FamilyID=e8ba3e56-d8fe-4a91-93cf-ed6985e3927b&displaylang=en

Also check out SecEdit at http://support.microsoft.com/kb/313222/

Wednesday, September 2, 2009

IPCop SMTP Trap

After an event where a visitor managed to generate enough spam that our mail server was blacklisted, I decided to configure our firewall, IPCop, to prevent a future occurrence.

After a visit to the forums as well as the blog, http://www.subvs.co.uk/smtp_blocking_with_ipcop, I wrote a shell script to effect the desired blocks.

The Setup:
  1. Guests are permitted only on the IPCop Blue network.
  2. We have a local mail server 6xx.1.2.3 attached to our IPCop DMZ (Orange) network
  3. Our primary domain MX server is reachable over the VPN at 192.168.y.y or over the internet at 5xx.1.2.3.  
  4. Users on our trusted Green network are permitted to send mail to our MX server over the internet or over the VPN.
  5. Our admin uses one local PC (192.168.x.x) for testing SMTP traffic so that IP is permitted to SMTP outbound anywhere.  
The Approach:
  1. Permit any outbound SMTP from GREEN_IPOK1
  2. Permit anyone on GREEN to connect to MX server (internet or VPN)
  3. Permit local mail server to send outbound SMTP anywhere from ORANGE
  4. Log and block all other outbound SMTP requests over the RED interface
The Limits:
  1. Guests on the BLUE network can not send email via SMTP.  Period.
  2. GREEN users can not send email except thru the MX server.
I chose to create a rc.firewall.smtp shell script file and then call it from within the rc.firewall.local script.  Made it easier to test without messing with the main firewall protections.

Caution:  Make sure that you run the rc.firewall.smtp stop before making any rule changes.  Eliminates a whole lot of cleanup later :)


The File:

#!/bin/sh
# Used to block outbound SMTP traffic
# Edited: AmAdmin 20090903

eval $(/usr/local/bin/readhash /var/ipcop/ppp/settings)
eval $(/usr/local/bin/readhash /var/ipcop/ethernet/settings)

# Local admin PC for SMTP testing
GREEN_OKIP1=192.168.x.x
# Local mail servers (VPN/MX/RELAY)
MAILSRV1=192.168.y.y
MAILSRV2=5xx.1.2.3
MAILSRV3=6xx.1.2.3

allow_smtp() {   
    # allow smtp outbound from networks to trusted mail server ips
    /sbin/iptables -$ACTION CUSTOMFORWARD -p tcp -i $GREEN_DEV -d $MAILSRV1 --dport 25 -j ACCEPT
    /sbin/iptables -$ACTION CUSTOMFORWARD -p tcp -i $GREEN_DEV -d $MAILSRV1 --dport 465 -j ACCEPT
    /sbin/iptables -$ACTION CUSTOMFORWARD -p tcp -i $GREEN_DEV -d $MAILSRV2 --dport 25 -j ACCEPT
    /sbin/iptables -$ACTION CUSTOMFORWARD -p tcp -i $GREEN_DEV -d $MAILSRV2 --dport 465 -j ACCEPT
    /sbin/iptables -$ACTION CUSTOMFORWARD -p tcp -i $ORANGE_DEV -s $MAILSRV3 --dport 25 -j ACCEPT
    /sbin/iptables -$ACTION CUSTOMFORWARD -p tcp -i $ORANGE_DEV -s $MAILSRV3 --dport 465 -j ACCEPT
    # permit smtp outbound from trusted GREEN ip addresses to anywhere
    /sbin/iptables -$ACTION CUSTOMFORWARD -p tcp -i $GREEN_DEV -s $GREEN_OKIP1 --dport 25 -j ACCEPT
    /sbin/iptables -$ACTION CUSTOMFORWARD -p tcp -i $GREEN_DEV -s $GREEN_OKIP1 --dport 465 -j ACCEPT
}

log_smtp() {
    # log all stmtp outbound from RED
    /sbin/iptables -$ACTION CUSTOMFORWARD -p tcp -o $RED_DEV --dport 25 -j LOG --log-prefix "SMTP_"
    /sbin/iptables -$ACTION CUSTOMFORWARD -p tcp -o $RED_DEV --dport 465 -j LOG --log-prefix "SMTP-SSL_"
}
   
block_smtp() {
    # block all stmtp outbound from RED
    /sbin/iptables -$ACTION CUSTOMFORWARD -p tcp -o $RED_DEV --dport 25 -j DROP
    /sbin/iptables -$ACTION CUSTOMFORWARD -p tcp -o $RED_DEV --dport 465 -j DROP
}

# See how we were called.
case "$1" in
  start)
        ## add your 'start' rules here
        ACTION=A
        allow_smtp
        log_smtp
        block_smtp
       ;;
  stop)
        ## add your 'stop' rules here
        ACTION=D
        allow_smtp
        log_smtp
        block_smtp
        ;;
  reload)
        $0 stop
        $0 start
        ## add your 'reload' rules here
        ;;
  status)
        /sbin/iptables -nvL CUSTOMFORWARD
        ;;
  *)
        echo "Usage: $0 {start|stop|reload|status}"
        ;;
esac

Thursday, August 27, 2009

Copy path to clipboard - XP64

This is a utility that I immensely enjoyed once I found it. I didn't
know how _much_ I used it until I moved to XP64 and 'lost' that
functionality. What a pain!

However, I finally found a replacement that "just works";
http://stefan.bertels.org/en/clipboardpath

I just installed V1.2 and it worked without even requiring a reboot!
One nice feature is the use of the CTRL key to translate the path to
the full UNC path. That could be very useful as the UNC is common
across all users but the share mapping may be different.

<clapping hands>

Sent from my Verizon Wireless BlackBerry