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Sunday, April 21, 2019

The default Time-To-Live (TTL) value for IP packets differs based on operating system. What is the default TTL value in Windows?

The default Time-To-Live (TTL) value for IP packets differs based on operating system. What is the default TTL value in Windows?

  • 128
  • 255
  • 32
  • 64
The default Time-To-Live (TTL) value for IP packets differs based on operating system. What is the default TTL value in Windows?

EXPLANATION

You can find your own TTL value from your self.

RUN->CMD->ping 127.0.0.1

C:\>ping 127.0.0.1

Pinging 127.0.0.1 with 32 bytes of data:
Reply from 127.0.0.1: bytes=32 time<1ms TTL=128
Reply from 127.0.0.1: bytes=32 time<1ms TTL=128
Reply from 127.0.0.1: bytes=32 time<1ms TTL=128
Reply from 127.0.0.1: bytes=32 time<1ms TTL=128

Ping statistics for 127.0.0.1:
    Packets: Sent = 4, Received = 4, Lost = 0 (0% loss),
Approximate round trip times in milli-seconds:
    Minimum = 0ms, Maximum = 0ms, Average = 0ms

C:\>


As you can see from the output, you got the TTL value. Since this website is hosted on a Red Hat system, it returned 57 which is close to 64 (TTL default value of Linux system). So, from this we can understand the OS of the remote system. Here are the default TTL values of different devices / Operating Systems :

Device / OS Version Protocol TTL
AIX TCP 60
AIX UDP 30
AIX 3.2, 4.1 ICMP 255
BSDI BSD/OS 3.1 and 4.0 ICMP 255
Compa Tru64 v5.0 ICMP 64
Cisco ICMP 254
DEC Pathworks V5 TCP and UDP 30
Foundry ICMP 64
FreeBSD 2.1R TCP and UDP 64
FreeBSD 3.4, 4.0 ICMP 255
FreeBSD 5 ICMP 64
HP-UX 9.0x TCP and UDP 30
HP-UX 10.01 TCP and UDP 64
HP-UX 10.2 ICMP 255
HP-UX 11 ICMP 255
HP-UX 11 TCP 64
Irix 5.3 TCP and UDP 60
Irix 6.x TCP and UDP 60
Irix 6.5.3, 6.5.8 ICMP 255
juniper ICMP 64
MPE/IX (HP) ICMP 200
Linux 2.0.x kernel ICMP 64
Linux 2.2.14 kernel ICMP 255
Linux 2.4 kernel ICMP 255
Linux Red Hat 9 ICMP and TCP 64
MacOS/MacTCP 2.0.x TCP and UDP 60
MacOS/MacTCP X (10.5.6) ICMP/TCP/UDP 64
NetBSD ICMP 255
Netgear FVG318 ICMP and UDP 64
OpenBSD 2.6 & 2.7 ICMP 255
OpenVMS 07.01.2002 ICMP 255
OS/2 TCP/IP 3.0 64
OSF/1 V3.2A TCP 60
OSF/1 V3.2A UDP 30
Solaris 2.5.1, 2.6, 2.7, 2.8 ICMP 255
Solaris 2.8 TCP 64
Stratus TCP_OS ICMP 255
Stratus TCP_OS (14.2-) TCP and UDP 30
Stratus TCP_OS (14.3+) TCP and UDP 64
Stratus STCP ICMP/TCP/UDP 60
SunOS 4.1.3/4.1.4 TCP and UDP 60
SunOS 5.7 ICMP and TCP 255
Ultrix V4.1/V4.2A TCP 60
Ultrix V4.1/V4.2A UDP 30
Ultrix V4.2 – 4.5 ICMP 255
VMS/Multinet TCP and UDP 64
VMS/TCPware TCP 60
VMS/TCPware UDP 64
VMS/Wollongong 1.1.1.1 TCP 128
VMS/Wollongong 1.1.1.1 UDP 30
VMS/UCX TCP and UDP 128
Windows for Workgroups TCP and UDP 32
Windows 95 TCP and UDP 32
Windows 98 ICMP 32
Windows 98, 98 SE ICMP 128
Windows 98 TCP 128
Windows NT 3.51 TCP and UDP 32
Windows NT 4.0 TCP and UDP 128
Windows NT 4.0 SP5- 32
Windows NT 4.0 SP6+ 128
Windows NT 4 WRKS SP 3, SP 6a ICMP 128
Windows NT 4 Server SP4 ICMP 128
Windows ME ICMP 128
Windows 2000 pro ICMP/TCP/UDP 128
Windows 2000 family ICMP 128
Windows Server 2003 128
Windows XP ICMP/TCP/UDP 128
Windows Vista ICMP/TCP/UDP 128
Windows 7 ICMP/TCP/UDP 128
Windows Server 2008 ICMP/TCP/UDP 128
Windows 10 ICMP/TCP/UDP 128

I will update this table in the future when there’s a release of new important OS whenever I get the time. You can get the short version of default TTL values by this table :

Device / OS TTL
*nix (Linux/Unix) 64
Windows 128
Solaris/AIX 254


 

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What is the correct syntax to run a error fixing check disk in a command prompt?

What is the correct syntax to run a error fixing check disk in a command prompt?

  • chkdsk /f
  • cd
  • ipconfig
  • dir 

EXPLANATION

 The cd command, also known as chdir, is a command-line OS shell command used to change the current working directory in operating systems such as Unix, DOS, OS/2, AmigaOS, Windows, and Linux. It is also available for use in shell scripts and batch files. The system call that affects the command in most operating systems is chdir that is defined by POSIX.



In computing, ipconfig in Microsoft Windows is a console application that displays all current TCP/IP network configuration values and can modify Dynamic Host Configuration Protocol and Domain Name System settings.

In computing, dir is a command used for file and directory listing, specifically in the command line interface of the operating systems CP/M, DOS, OS/2, Singularity, Microsoft Windows and in the DCL command line interface used on VMS, RT-11 and RSX-11. The command is also supplied with OS/8 as a CUSP. 

Checks the file system and file system metadata of a volume for logical and physical errors. If used without parameters, chkdsk displays only the status of the volume and does not fix any errors. If used with the /f, /r, /x, or /b parameters, it fixes errors on the volume.

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What is the range of well known ports assigned to common protocols and services

What is the range of well known ports assigned to common protocols and services

  • 0-49151
  • 1-1023
  • 0-49152
  • 0-1023 

EXPLANATION

logical connections, provided by the TCP or UDP protocols at the Transport layer, for use by protocols in the upper layers of the OSI model.
 
logical connections, provided by the TCP or UDP protocols at the Transport layer, for use by protocols in the upper layers of the OSI model.


Well Known ports range from 0 to 1023 and are assigned to common protocols and services.

 


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What is the MS-DOS (CMD Prompt) command that enables a user to change the title of their MS-DOS (CMD Prompt) window?

What is the MS-DOS (CMD Prompt) command that enables a user to change the title of their MS-DOS (CMD Prompt) window?

  • winid
  • set title
  • topbar
  • title 
What is the MS-DOS (CMD Prompt) command that enables a user to change the title of their MS-DOS (CMD Prompt) window?

EXPLANATION

Launch Command Prompt and type the following command title [name]. This will change your title name instantly,
but you will have to type this each time you launch it.

SOURCE

https://www.addictivetips.com/windows-tips/how-to-change-name-in-the-title-bar-of-command-prompt/

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What is the maximum speed 802.11ac standard can transfer at?

What is the maximum speed 802.11ac standard can transfer at?

  • 1.3Gbps
  • 0.45Gbps
  • 6Gbps
  • 450Mbps 
What is the maximum speed 802.11ac standard can transfer at?

EXPLANATION

802.11ac is the latest generation of IEEE standards. 802.11ac has improved on the previous standards regarding bandwidth. 802.11ac used dual-band wireless technology.

It can support connections using the 5GHz frequency band. 802.11ac supports a maximum speed of 1.3 Gbps when using three streams. This is the first specification have reached the 1 Gb mark and is also called the Gigabit Wi-Fi.

Pros of 802.11ac

  1. Supports data transfer rate of 1.3 Gbps
  2. Backward compatibility with 802.11b/g/n
  3. Highly beneficial in a network with a large number of users.

 

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What is the importance of 12/31/1969 to the IT world?

What is the importance of 12/31/1969 to the IT world?

  • New Years Eve
  • The first release of Windows 1.0 was shipped
  • The Beginning of That 70s Show
  • The beginning date of Unix and where it starts counting time from 
What is the importance of 12/31/1969 to the IT world?

EXPLANATION

 Linux is following the tradition set by Unix of counting time in seconds since its official "birthday," -- called "epoch" in computing terms -- which is Jan. 1, 1970.

A more complete explanation can be found in this Wired News article. It explains that the early Unix engineers picked that date arbitrarily, because they needed to set a uniform date for the start of time, and New Year's Day, 1970, seemed most convenient.

 The Unix epoch is midnight on January 1, 1970. It's important to remember that this isn't Unix's "birthday" -- rough versions of the operating system were around in the 1960s. Instead, the date was programmed into the system sometime in the early '70s only because it was convenient to do so, according to Dennis Ritchie, one of the engineers who worked on Unix at Bell Labs at its inception.

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How do you block a user from opening a folder, when that group has full permissions?

How do you block a user from opening a folder, when that group has full permissions?

  • In AD uncheck Allow on the User in the group
  • Explicit Deny User on the folder 
  • Click Stop Permissions on the User in AD
  • Create Exception on the folder for User 
 

EXPLANATION

Access Based Enumeration will be your best solution. That way even though the user account may be able to see a share, they can't see any of the contents. You could go a step further and create a Deny-SMB security group with that account as its sole member and then nest all of your other user level security groups in a group that is granted permissions to access shares.


Overall, more information is going to make the best possible route easier to recommend

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