Posts Tagged ‘Comcast installation: Private Busines’

Comcast Installation: Private Business


After weeks of planning here we are … Waiting for the cable man!

Oh, but this time he is arriving to a business site – not my house. The good thing… he did called and said he was running late.  An hour later two men  are here, tools on waist and ready to install  new phone service and new Internet Access.  This service will be replacing a traditional Cimco Communications T1 circuit and a tradition POT analog phone service from ATT.  The coax-cables were ran prior to this visit.

The price and the Technology – Broadband – all too familiar to home users is now available to the business sector!  Several questions are in the back of my mind at this point – While the price and the promised  speed-gain (1.5Mb 20Mb download!) are great,  can’t help but to ask myself will it be reliable?  We will have to wait and see.  I love Comcast speed at home but outages are all to comon in my area .   Too common and too frequent…

While waiting for the green light to do my part; Router configuration, firewall configuration, and Remote Desktop Access configuration – I do other things…  My goal is to configure a Cisco Router pass their access point (gateway / Modem).  Traditionally the use of Cisco Access List  is one way to protect intruders from accessing the private network.  In this case the Router I will be using is the existing Cimco Router. ( At this point My understanding is that this is an Ethernet to Ethernet Router – Right? So I charge on and work on the script to add to this router … NAT table configuration, Allow Access List, Deny list… 

I mapped the LAN and now I have all my internal MAC and IP Addresses for each of the computers I need to access remotely… I am also waiting on Cimco to contact me back with the user ID and the Password for the existing Cisco Router (My client is buying this router ) so I can change the internal script code … all alone users are using the Internet to send and receive email messages – or perhaps using the internet to viewing their favorite fantasy team who knows?

An hour later one of the men – The one with all the cool tools on the waist – is here and ready to hand out the IP addresses I need to configure the Cisco Router.  Ready? Yes… Local IP Address on the modem is such and the Public IP Addresses are such and the DNS are… and so on.  I get all the information … Meanwhile the other man is on the phone calling Comcast, testing the phone lines while at the same time helping a team member solve other problems (using a two way radio) at another site with another client – Fun stuff ! 

I can’t connect at this point he needs to get the phone lines punch down and active.    … another 40 minutes later,   They are ready and walking out the door.  “Oh, here is the user ID and the Password to the SMC modem… Just in case you need to do changes!”  Ok, I said… I take the information, shake hands and wave good bye.

First things first… Do I have access to the existing Cisco Router?  No, Cimco has not called back… Ok, Lets use my laptop to test the Comcast Circuit? – (or Connection).  Wow,  this SMC Modem, has a DHCP Built in!… lets look deeper … while they are calling this a modem I found it is much more than that.  Features like Firewall and NAT are also built into this modem – ….   I got a call from Cimco,  I ask  for the user ID and password to the existing router- they do not want to give it to me – they have to change it first…    I explain to the Tech at Cimco that the client is buying the Cisco router from them after the contract is over -5 days from now.  So I’m put on hold … 

He is now back… I continue to explain what I need to do to the router.  I will be assigning a public IP Address to one of the Ethernet ports and a Private Ethernet address ( to the Local Ethernet Segment.  Great, one problem !!! This Cisco Router is a T1 Router and it only has one Ethernet port and a WIC card for their T1 service.

Plan number 2? ok, it way my first plan. To purchase a new Cisco 800 modem router with Ethernet to Ethernet Router firewall and NAT features – about $400 to $500.   So here we are…

I have my laptop connected to the Comcast SMC modem and “” is showing 37mg download and 1.5Mb upload — this is too cool, I can’t deprived my client from the benefit of this download speed – right?  so Idigg into the features of these SMC Router and found that it has a DHCP Server built in, it also has a port redirector built in, Plus a NAT 1-to-1 function – This feature to be used if I wanted to connect the Cisco router to it and assign a public IP Address… However in the absence of the Cisco Router ….

I tested and play with the settings and found that I could in fact use this modem – now I think that this is more than a traditional modem – this is a router with lots of cool features built in.  Did I mention that it also has a Firewall feature, plus the ability to block access to web sites?  All too cool.

So, I change the Local Ethernet segment IP Address to match the IP address of the old Cisco Router turn off the DHCP Function since we are using the Local MS 2003 server to do this.  Now I disconnect the old router and connect the ethernet cable to the switch port.  Bingo!  It all works.  Some local computers have to be restarted but most of them are able to access the internet right away.  Lets do some more testing,  …connect to  – for testing purpose only- and started playing a movie at several computers at the same time – wow it works!

Finish the remote access list using the port redirection feature in the SCM modem configuration. Found that he public IP Address used on the modem/router is working and as it needs to be static it should not change.  I also have 5 extra public IP addresses to be redirect via a 1-to-1 NAT or via direct connection to the SMC extra Ethernet ports.   However,  in this case all I need is the IP address already assign to the SMC Router!   This is a static public IP Address.   I now call the DNS Manager and ask for the A record to be change to the new public IP address and Bingo!  few minutes later it is propagated and available to be use.

I Did some testing using  Windows XP’s  “Remote Desktop”   connected to an external computer and from that external computer  remote access  into the local computers – It all works.

So, No need to purchase a new Cisco Router!  with the build in NAT port redirector in the SMC modem the day was saved!

Speed during the initial testing was great…. some sites appear faster than others  … but keep in mind that the speed is at the least common denominator.  If the site you are connecting  is set for 1Mb upstream access that’s all you will get but, there is the potential for higher download bandwidth.

Cesar Lopez

Best Networks Inc

(773) 908-7378

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