TCP/IP Utilities

Utility is a program or application that enhances an operating system's capabilities by performing a special function not provided by the operating system, such as a "print" utility or a "search and replace" utility.  There are three common TCP/IP utilities: Ping, Tracert, and NSlookup, which are available on both a Macintosh and Windows-based computer.

These utilities will help you diagnose and troubleshoot issues by verifying:

(PING) That a specific IP address or URL is active and also able to send/receive information

(TRACEROUTE) That a route/switch that could be causing an issue is identified

(NSLOOKUP) Who hosts the domain, either by IP address or URL

PING

This command verifies that a specific destination IP address exists and is operating (i.e., accepting requests).  Ping works by sending an echo packet to a specified host and waiting for a reply.  All hosts are supposed to bounce the packet back so that the program can determine if the host is online or not.

Ping can also be used to:

1. Determine how long it takes to receive a response from a specific address (to calculate latency)

2. Determine a host's dot address.  Ping will not help if you are having any non-connectivity related problems with applications like Microsoft Office, etc.

The IPv4 syntax for the ping command is: ping [destination computer or IP address] and the IPv6 syntax for the ping command is: ping6 [destination computer or IP address]

You can set any of the following options when using the ping command:

-n – Specifies the number of packets to transmit.  Default is four.  In the example below, the ping count is 10.

-a – Resolves IP addresses to host names.

-l (Lowercase "L") – The size of the packet being transmitted (default is 32 bytes).  In the example below, the packet size is 50. 

NOTE: The larger the packet, the longer it takes to get a reply. 

 -t – Used for a number of things, such as detecting if the customer has a firewall.  This command will ping an IP address continuously until you press CTRL-C.  To determine if the customer has a firewall, run the command while the customer reboots the PC.  If a firewall loads, the ping replies will stop (unless you press CTRL-C). 

Tracert is a diagnostic utility used to identify equipment issues.  It traces the route taken to a destination by sending echo packets with varying Time-to-Live (TTL) values.  For example, we may only set the TTL to 10 hops.  This tells us the number of hops that a packet of information makes from one point to another in the network.  Each router/switch encountered along the path decreases the TTL value by 1 before forwarding it.  So, if the max TTL is set to 10 hops, it will count down from 10 to 9 and so on until it either is at 0 or finds the piece of equipment it was tracing to. 

When the TTL on a packet reaches 0, the router is supposed to send back a Time Exceeded message. Some servers just drop the request without sending back a message, or they block the packets and return a "Request Timed Out" message. In this case, a row of asterisks (*) is displayed. Tracert determines the route by sending the first echo packet with a TTL of 1 and incrementing the TTL by 1 on each subsequent transmission until the target responds or the maximum TTL is reached. The route is determined by examining the ICMP Time Exceeded messages sent back by intermediate routers.

NOTE: While tracert is an effective tool used to determine the path to a destination site, it is not always the best tool for determining packet loss or latency along that path. Because of the way that tracert works (it only pings each hop three times, therefore providing a very small sample of data), the times listed at each hop may give an inaccurate representation of the status of the network. Ping is a much more effective tool for determining packet loss and latency.

NOTE: The first column is the hop number.  The next three columns show ping times between you and that particular host.  The last column shows the name of that server, or gateway, and its IP address.

A few important facts about Internet speeds related to latency:

Hop times of less than (<) 100 milliseconds are normal for short (<100 distances.="distances." medium="medium" miles="miles" p="p" to="to">

Hop times of <200 although="although" applications.="applications." cause="cause" distances="distances" do="do" for="for" ideal="ideal" in="in" longer="longer" miles="miles" milliseconds="milliseconds" most="most" not="not" p="p" problems="problems" the="the" us="us">

Sustained, consistent hop times greater than (>) 250 milliseconds need to be investigated. Occasional response times of >250 milliseconds do not need to be investigated (these occur due to momentary network congestion). 

The Traceroute command line syntax is:

tracert [-d] [-h maximum_hops] [-w timeout] target_name >> textfile.txt

Traceroute Command Line Options:

-"d" – Does not resolve addresses to hostnames. 

-"h maximum_hops" – Maximum number of hops to search for target. 

-"w timeout" – Wait timeout milliseconds for each reply. 

">> textfile.txt" – Writes the results to textfile.txt in the same directory you run tracert from. 

NSlookup

This diagnostic tool displays information from the DNS name servers.  You can enter a host name and find the corresponding IP address.  You can also enter an IP address, and the corresponding host name will be displayed.  This is known as a "reverse lookup".

The command line for NSLookup is:

C:> nslookup [domain or IP address]

NSLookup Command Line Result

NSlookup by URL: 

When starting NSLookup, you may receive the following errors:

Can't find server name for address example: w.x.y.z Timed out.

NOTE: w.x.y.z is the first DNS server listed in the DNS Service Search Order list.

The error indicates that no servers have been defined in the DNS Service Search Order list.  To correct this problem, add the IP address of a valid DNS server to this list.

Can't find server name for address 127.0.0.1: Timed out

This error indicates that the DNS server cannot be reached or the service is not running on that computer.  To correct this problem, either start the DNS service on that server or check for possible connectivity problems.

100 Days With Mr Arrogant

After being dumped by her boyfriend just before their 100 day anniversary, Ha-Young (Ha Ji-Won) meets a college guy named Hyung-Joon when she kicks a can that accidentally hits him in the face and causes him to scratch his Lexus. He demands she pay him $3000 on the spot. She escapes from him, leaving her wallet behind.

Hyung-Joon stalks her, demanding money to pay for his car. Since she is a poor high school student Hyung-Joon writes up a "Enslavement Agreement" for Ha-Young in order to pay for the damage to his car. Ha-Young is thrown into a nightmarish slave life for 100 days, running his errands, i.e.: cleaning his house, carrying his shopping, and cleaning his car.

By accident she finds out that the damage to Hyung-Joon's car that's only $10! She then takes her revenge. However, before she knows it Hyung-Joon shows up at her house as her new tutor! He once again takes advantage of her, but soon Ha-Young finds herself falling head over heels for Hyung-Joon. But what happens when he drops out of her life just when she needs him most?

The original Korean title can be literally translated as "my love, the asshole," or, more roughly, as "my love, the no-manners".

200 Pound Beauty

Han-na is an overweight phone sex employee and a ghost singer for Amy, a famous pop singer who actually lip syncs. Instead of being famous for her own amazing vocal talent, Han-na hides behind Amy's performance stage and sings during Amy's concerts, and records all of Amy's songs. One day, Amy ungratefully humiliates her in front of the music company's director Sang-jun during his birthday party, knowing full well that Han-na has a crush on him. While crying in the bathroom, Han-na overhears Sang-jun telling Amy that even though they are just using Han-na for her voice, they must be kind to her so she will not walk out on them. Heartbroken, Han-na attempts suicide but is interrupted by a phone call from one of her phone sex regulars who happens to be a top plastic surgeon. She decides to get head-to-toe plastic surgery instead. The surgeon at first refuses to operate on Han-na, but Han-na threatens to blackmail the surgeon by telling his wife about his calls. Then, Han-na makes a moving speech that she does not want to undergo surgery merely to be beautiful, but for the sake of love and as a boost in confidence, and the surgeon is deeply moved. Han-na puts herself in seclusion for a year as she recovers from the changes.

When she comes back from the hospital, Han-na is incredibly beautiful and slender. No one, not even her best friend, Jung-min, recognizes her. With Jung-min's help, she creates a new identity for herself; she is now a Korean-American from California named Jenny. After auditioning to be Amy's secret vocalist again, she earns her own recording contract instead from Sang-jun, claiming that she is "all-natural". In the meantime, Amy, oblivious just like everyone else of Han-na's new identity, desperately tries to find Han-na so that she can record her own postponed album (since she cannot sing the songs herself) by spending time with Han-na's father who is in a hospital due to mental problems, possibly Alzheimer's. Meanwhile, romance begins to blossom between Jenny and Sang-jun, as he continues to promote Jenny, in effect boosting Han-na's confidence in her new self. However, Amy, through spending time with Han-na's father and Jenny, eventually realizes that this Jenny is actually Han-na in disguise.

During a date one night, as sparks fly, Jenny strips for Sang-jun in the character of a nurse, through a phone sex session. After Jenny has fallen asleep, he sees the African character Jenny had drawn on the glass and realizes that he had seen it before. He remembers that Han-na had drawn exactly the same signs on a sheet of music. Then he adds up all of the signs and realizes as well that Jenny is actually Han-na but he keeps this information to himself.

Jenny's debut single "Maria" becomes a hit and the recording company holds a party to celebrate its release. On the day of the party however, Amy brings Han-na's father in an attempt to blow her cover. Han-na's father tries to return Han-na's Barbie doll to her, which had always been Han-na's favorite childhood gift from him. Startled by the sudden appearance of her father and not knowing how to react in front of all the people, including Sang-jun, Han-na denies knowing her father and calls him a fan instead when Sang-jun asks her if the old man is her guest. As her father keeps insisting on giving her the doll, Sang-jun drags him away from Jenny and accidentally knocks him down onto the floor. Desperate to keep her true identity a secret, Han-na makes no move to help her father. It is Jung-min who finally helps him up, casts Jenny a furious look and leads Han-na's father away from the party.

After the party, Sang-jun and Jenny are the only ones left in the room. Sang-jun reveals to Jenny that he knows her true identity but is now cold and distant. He seems unable to forgive her for lying to him but says that he will still work to promote Jenny and carry on with her concert scheduled the next day. Han-na breaks down at this point, heartbroken and unable to pretend to be someone else anymore. Han-na tells him that it is incredibly frustrating and painful not being able to just be herself but have to live a lie, especially in front of him. The surgery that took a whole year to recover from was not nearly as painful as realizing that she still could not be close to Sang-jun. As Sang-jun tries to comfort her, she brushes away his efforts saying, "You broke my heart. Tissue paper cannot fix it."

Sang-jun still insists on continuing with Jenny's first concert, despite protests from the company boss. Later, he encourages a distraught Jenny to do this concert, not for the sake of the fans or the company but for herself, thus implying that he has forgiven her and will continue to support her. At the concert, Jenny can't sing and later breaks down from the pressure of seeing her father being dragged away by security and tells everybody to stop. She then reveals to the public that Jenny is a "fake," and that she is not "all-natural", as she had claimed, but is "plastic". However, nobody seems to believe her. She proceeds tearfully to tell the large crowd her story: how she has abandoned everything that is dear to her - her best friend and father - to get to where she is. She also tells the crowd about how on the way to fame and fortune she has also lost her own identity and that she now no longer knows who she is. Just then, the screens behind her on the stage start to show a clip of the old, obese Han-na, singing angelically. Han-na turns around and sees her old image and tells the crowd that the image is the real her. The crowd, moved by her sincere confession, responds by chanting "It's okay," and Han-na rekindles her relationships with her father and best friend. She drops the stage name Jenny and re-releases a CD with her own name, Han-na, and becomes a highly successful music artist, gaining many fans and anti-fans along the way. Sang-jun realizes the very thing about Han-na that had always drawn him to her was Han-na's innocence. However he also realizes that she has moved on and is now content with who she is.

At the end of the movie, Jung-min also asks to get head-to-toe plastic surgery.