Taher's World

Denial-of-Service Attacks

2009-07-09T14:58:00.001+07:00

Denial-of-service (DoS) attacks attempt to deny valid users access to network or server resources by using up all the resources of the network element or server. By using up all the resources, a malicious user can deny access by valid users.
There are many kinds of DoS attacks. Some can be thwarted by using stateless filtering, while others may require state (flow) information. The following list describes some common DoS attacks:
Synchronization (SYN) flood—Attempting to create a large number of Transmission Control Protocol (TCP) connections by sending synchronization packets but not completing the connections. Known as half-open connections, these incomplete SYN packets take some time to be removed. Because servers often have a limit on the number of connections allowed, this type of attack denies service to valid users.
Internet Control Message Protocol (ICMP) or User Datagram Protocol (UDP) flood—Preventing access to a network or host with a flood of either UDP or ICMP packets above that which the network elements can handle.
Ping of death—Sending very large and fragmented ICMP packets that may cause some IP stacks to crash.
Land attack—Sending TCP SYN packets with the source and destination address set to the address of the machine being attacked.
Teardrop—Sending the first and second part of a TCP packet in different IP fragments with overlapping offsets, causing the target host to crash.
IP source route attack—Using the source route option, an attacker can masquerade as a trusted host.
IP multicast source—Using a multicast source to cause a response that consumes network resources.
TCP state machine attacks—Setting both the SYN and finish (FIN) bits or the FIN bit with no acknowledgment (ACK) bit within TCP packets.
Other UDP issues—Sending a UDP echo to an IP broadcast destination addresses (called a fraggle attack) consumes network resources (because all hosts on the subnetwork respond). Sending a UDP packet in which the UDP length is less than the IP length can cause some systems to crash.

CRM 4.0 customizations for improving performance

2009-07-08T10:04:00.001+07:00

Organizations may need to use MS Dynamics CRM in WAN environment where performance is a big issue. To run MS Dynamics CRM in WAN environment, we should remember some tips and tricks.

The following tasks should be done:

1. Customized the Account and Contact forms
--Disabled Forms Assistant
--Changed the Default Public View to display two fields
--Removed selected fields and search fields
2. Changed Number of Fields returned to 25
3. Specified to show only Sales in Workplace Pane
4. Changed the security role to only allow the Contact and Account Entities
5. Disabled Duplicate Detection
6. Removed as many items as possible from the left Navigation Bar (except Workplace)
7. Customized Accounts and Contacts grid to show only the Name and a few other key fields
8. Removed the majority of items in the left Navigation Bar of the Account and Contact forms

Detail of Customizations

1. Disabled the Forms Assistant
2. Changed the Default Public View to display two fields

3. Removed fields:
 Account form: Other Phone; Fax; Phone; Address2; Address3
 Contact form: Street2; Street3; Country/Region; Phone; Salutation; Middle Name; Home Phone; Fax; Pager

4. Removed search fields:
 Account form: Account Number; E-mail
 Contact form: All except FullName

5. Changed the Number of Fields returned to 25

6. Modified the Workplace Pane to show only Sales

7. Changed the security role to allow only the Contact and Account entities

8. Disabled Duplicate Detection

9. Removed all unnecessary items (except Workplace) from the left Navigation Bar

10. Removed unnecessary items from the left Navigation Bar of the Account/Contact forms.

Common Mistakes for Network Administrators

2009-07-08T09:51:00.001+07:00

1. Not changing the default passwords on all network devices.
2. Sharing a password across multiple network devices.
3. Failing to find SQL coding errors.
4. Misconfiguring your access control lists.
5. Allowing nonsecure remote access and management software.
6. Failing to test noncritical applications for basic vulnerabilities.
7. Not adequately protecting your servers from malware.
8. Failing to configure your routers to prohibit unwanted outbound traffic.
9. Not knowing where credit card or other critical customer data is stored.
10. Not following the Payment Card Industry Data Security Standards.

Saint Martin is loosing its charm

2008-06-18T14:04:00.007+06:00

Taher Ali

When I visited Saint Martin for the first time, I found that it was the best place for enjoying vacation. At the same time, this was the most beautiful place. To me anyone can go there for thousands time and he will not be bored. But, I was wrong. When I went there for the second time, I found this was a boring journey.
People are also working to reduce the gorgeousness of Saint Martin. All the mobile companies have setup their network and they are actually making obstacles for enjoying leisure. Foods are very expensive than before. At the same time, the quality also deteriorated. You will not get any place to enjoy your leisure. How sad!

However, it was nice with having friends and colleagues around. All the peoples were very funny. I have to mention one name 'The Jacks Bhai'. He gave a very enjoying session at the hotel room when all of us were very tired. Everyone will remember this for .........

SoftExpo 2008

2008-06-17T23:33:00.007+06:00

Taher Ali

Zillur bhai, Rashed and I represented Microsoft Dynabmics NAV and CRM in SoftExpo 2008. Microsoft Dynamics NAV is an ERP for mid size company and CRM is a web based customer relationship management software. During this exposition, I felt that the real customers or software people were not visiting. Most of the people were interested in the price of Windoes XP and computers (hardware related).

This happens from the inception of software exposition. What's the problem? The concerned people should take care of this. Most probably the message don't reach to the target people. We should have proper planning to improve this.

Visited Sylhet in Winter

2008-06-10T23:44:00.008+06:00

Taher Ali

Although, the most beautiful place in Bangladesh is Bandarban, I enjoyed the sylhet journey most. Everything was managed properly and ultimately the team was very happy. I think everyone of this team will agree with me.
The weather was very cool at that time. We couldn't see even 10 feet clearly as the weather was foggy. We tried to visit the whole Sylhet within two days and we were successful. To me the most beautiful place in Sylhet is the Tamabil. You will see another NAIGRA JOLPRPAT here as the local inhabitants have named it like this.

Enhance Writing Skills

2008-06-09T08:34:00.008+06:00

Taher Ali

The most effective way to enhance our writing skills is to write more and more. We should write lot with reading. Without practice it is almost impossible to enhance our writing skills. But, this is quite difficult to practice writing. We will need more pen and paper. In addition, the most boring thing is to sit with pen and paper.
Now we can write blog in Internet which can definitely enhance our writing skills. At the same time, we will not need pen and paper. We will also have archive of what we write. This will work if we want to increase our writing skills.
Take care all.

Bandarban - The most beautiful place

2008-06-08T14:11:00.004+06:00

Taher Ali

Bandarban is the most beautiful place in Bangladesh. I visited some places of our country and found that Bandarban is the best place to enjoy vacation. But, you have to be physically fit to go there.

If you want to go there, it will be better if you don't use any vehicles. You will get the taste of real adventure.

Add value to my account

2008-06-06T00:41:00.000+06:00

Whenever you search anything from this site or go to any advertisements from this site, it will add values to my account. If you have any site like this, let me know. I will do the same thing that can add values to your account.

Make this your homepage or add this to your favorites so that you can use it to search your important information.

Take care all.

TechVELOCITY Second Round

2008-06-04T01:22:00.000+06:00

The second round of techVELOCITY has been completed successfully. This tine the day was a liitle bit different. The scheduled presentation was postponed as the plan for the coming year was announed on that day and it took a lot of time than expected. Hopefully, the presenter will become more prepared.

Taher Ali

2008-05-27T15:18:00.002+06:00

Taher Ali

Hello! This is Taher Ali.