I think Nmap is by far the best portscanner around if you want to do some serious port-scanning. Nmap performs a DNS resolution by default. This is good for obtaining the fully qualified domain names (FQDN), however, in some cases when you are scanning huge networks spanning several class Bs, it can have a significant effect on the duration of the scan.
Although using the -n parameter can completely stop nmap from performing any resolutions, but sometimes there’s that fine granularity that you need, i.e., you want to perform name resolutions but not if it exceeds a certain amount of time. I have to say that I wouldn’t have even craved for such an idiosyncratic feature, had it not been for nmap. Fyodor has been awesome enough to provide fine-grained control over port-scanning to your heart’s content.
So I opened up the nmap code, trying to figure out if I could fine tune that feature myself and I was not at all surprised that there were several comments in the code that would give you the impression that the authors of nmap have been considering this feature.
At this time it seems that the timeouts for the DNS servers are being read out of an arrayname:
static int read_timeouts[][] in nmap_dns.cc.
The way the code works is, this array has retransmission timeouts. Each row of this array represents what retransmission timeouts that nmap will follow depending on the number of DNS servers provided.

In nmap 4.76, therefore, if you specify one DNS server (or only one entry exists in /etc/resolv.conf) nmap will wait 4000ms, then another 4000ms followed by 5000ms before giving up. But if you do specify two DNS servers, then for the first DNS server the timeouts are 2500ms followed by 4000ms and then the same is tried for the 2nd entry in the DNS servers. Therefore, it seems that nmap will wait 13 seconds at max before giving up on the DNS resolution of a host. Imagine scanning a class B and having to wait 13 seconds for each of the hosts to resolve. It would be a significant overhead.

Of course, one can find other things to do if the IP address space is not DHCP, e.g., starting a separate list scan (-sL) and a portscan (with -n) simultaneously so that the DNS resolution timeouts do not result in a major impact as far as the portscanning itself is concerned.
There could be pros and cons to this as well which I may have failed to consider. But at this time it seems that it might be the most judicious approach.

Using watermarks in word documents looks really cool. But the problem occurs when the documents become too big. In such cases, the document becomes exceedingly slow to react to scrolling. Adobe PDF conversion is an even bigger problem.
To remove the watermark it is simple enough : Format -> Background -> Printed Watermark. Then click on “No watermark” and you are golden (or you should be golden).
I’ve observed that the watermark does not get removed many times when you have too many sections in the document.
In such cases: Goto View -> Header and Footer. Click on “Show/Hide Document Text”.
You should see that all your text has disappeared except the watermark. Click on the watermark and you should be able to select it like a floating image. Press the “delete” key and lo! behold! the watermark is gone.
This took me a while to figure out and it was quite frustrating. I hope this post helps someone!

If you are installing Windows Driver Kit (WDK) from Microsoft and you choose to install the Device Simulation Framework (DSF) for USB and such devices, then you need to have the DCOM Server Process Launcher service running otherwise you get errors as cryptic as:
Unexpected Installation Error. Error in installing.
I wish there was more information that could be given in the error. Since I figured this out with only trial and error, I thought I’ll post the solution to this error.

If you want to find out the components of a site’s certificate the following commands will help you.
If you want to find if the certificate is signed with the weak MD5 signature algorithm:
$ echo | openssl s_client -connect webserver.example.com:443 2>/dev/null | sed -ne ‘/—–BEGIN CERTIFICATE—–/,/—–END CERTIFICATE—–/p’ | openssl x509 -text | grep “Signature Algorithm”| gawk ‘{print $3}’

$ echo | openssl s_client -connect 167.155.38.24:443 2>/dev/null | sed -ne ‘/—–BEGIN CERTIFICATE—–/,/—–END CERTIFICATE—–/p’ | openssl x509 -text | grep “Exponent”

It’s a brand new day with no novelty! Back to the lab today trying to now get access to the packet data to calculate the hash values. I suspect that inside netfilter’s sk_buff structure there’s an unsigned char* data field. This probably is exactly what I need to get the hash values. There’s this awesome link which has great information about sk_buff structure. The unsigned int len; has the size of the complete input data including the headers. I guess if this len value == size of the actual data for the IP header (which could be TCP header / UDP header / ICMP header) then if we are using chunks of this data to find hashes then the following algorithm could be used:

no_of_chunks = len / BYTE_SIZE_FOR_SIGN;

for (int i = 0; i < no_of_chunks; i++)
{
  storeInTable(hashRabin(data,i*BYTE_SIZE_FOR_SIGN,
               (i+1)*BYTE_SIZE_FOR_SIGN - 1 ,0));
}
storeInTable(
hashRabin(data,no_of_chunks*BYTE_SIZE_FOR_SIGN,
        no_of_chunks*BYTE_SIZE_FOR_SIGN+addendum, 0)
);

This are my initial thoughts let’s see how it works out!

-Rajat.
Rajat’s Homepage

So I decided to use WPA2 Personal with AES+TKIP on my new Linksys WRT54GL router after my old D-Link router died. However, there were some issues in getting it to work on Kubuntu 6.10 Edgy Eft with my Intel Wireless IPW3945abg.
So I decided to put my /etc/network/interfaces and the /etc/wpa_supplicant.conf files up here for reference:
Suppose BLAH is my ESSID name. The psk value is an altered value for elucidation purposes only:

ctrl_interface=/var/run/wpa_supplicant
ctrl_interface_group=0
eapol_version=1
ap_scan=2
fast_reauth=1

# WPA-PSK
network={
ssid="BLAH"
proto=WPA RSN
key_mgmt=WPA-PSK
pairwise=TKIP
group=TKIP
psk=aaaa3fa7bbbbccccf6d44e199ecb2bebccccad25a0778beeee104db0b3fffff7
}

The value of the PSK command was obtained by using the value associated with the prefix “psk=…” after issuing the following command:

# wpa_passphrase BLAH passphrase
network={
       ssid="BLAH"
       #psk="passphrase"
       psk=aaaa3fa7bbbbccccf6d44e199ecb2bebccccad25a0778beeee104db0b3fffff7
}

The /etc/network/interfaces looked like this:

auto lo
iface lo inet loopback

auto eth1
iface eth1 inet dhcp
wpa-conf managed
wpa-driver wext
wpa-ssid BLAH
wpa-ap-scan 2
wpa-proto RSN
wpa-pairwise TKIP
wpa-group TKIP
wpa-key-mgmt WPA-PSK
wpa-psk aaaa3fa7bbbbccccf6d44e199ecb2bebccccad25a0778beeee104db0b3fffff7
pre-up wpa_supplicant -Bw -Dwext -i eth1 -c/etc/wpa_supplicant.conf
post-down killall -q wpa_supplicant

Once I was done with this configuration all I had to do was, issue the following command to get wireless working with WPA2 and TKIP:

# /etc/init.d/networking restart

Interestingly enough, I found last week that the new Nessus 4.2.0 works by default as a web interface. Gone are the days of using the NessusClient and connecting to TCP port 1241 and using it to connect to the nessusd. Connecting to local TCP port 8834 (https://localhost:8834) brings you to a web interface that you can use to connect to the new Nessus daemon. The nesssusd listener does not even listen on port 1241 by default.
I’ll shortly get used to it but I know the transition would be slow for me …. after it takes getting used to when you completely change the architecture after maintaining it for at least a good 7 years or so!