Jesus 'n Jim

A mainly PC (some Mac) site w/Software, Computer Repair Info, How-To's on Using Computers
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Networking

 

Overview

This is the base page of the section of Networking.

The content you are looking for can be found via the navigation to your left ←. some of these folder index pages have content, but most like this one don't.

the

IP info

this must be run from a cmd shell run as Administrator. it gives information about what programs are connecting to the inernet on your computer. I name the file ip-info.cmd

netstat -a -f >     "%USERPROFILE%\Documents\ip-exes.txt"
netstat -b -f >> "%USERPROFILE%\Documents\ip-exes.txt"
netstat -e -s >> "%USERPROFILE%\Documents\ip-exes.txt"
start notepad          "%USERPROFILE%\Documents\ip-exes.txt"

how to clear the DNS (Domain Name Service) cache

windows via cmd shell:

nbtstat -R
ipconfig /flushdns

it might also be a good idea to reboot on some windows OS combinations with service packs and updates like XP SP3. this cmd shell file (DNS changes, especially on XP) still seems to require a reboot afterwards.

You have to reboot afterwards. I noticed that with some browsers, DNS is still cached even though I have made new entries in my hosts file, for a while, maybe an hour or two - if I keep refreshing the page, eventually the cache gets flushed, not sure why this is. changing the hosts file used to have immediate effectiveness in XP, etc but not anymore.

This as a cmd shell script (windows)

Download Now
flush-DNS.cmd - source and executable (9/19/2014, 1KB)


Download Now
XP-no-negative-DNS-cache.reg - installer with embedded source (9/19/2014, 1KB)


line quality test

ask your ISP's support to do a line quality test if you are having trouble. things to check:

  • on your modem, are all the lights on as "high speed" and working properly according to the modem manual? (google the manual to find out)
  • is your modem cutting out once in a while? or is it a solid performer? if it's cutting out, there could be line quality problems. if you are using ethernet, check yourethernet cables and wiring, you can pick up a byte brothers or vdv mapmaster for cheap to check cables (don't use the tester on live wiring). work with technical support to help you fix any line issues. if you need to schedule a technician to come out to fix a line problem for something that you can't fix yourself, do so.
  • if an ethernet cable is physically damaged, buy a new one, they are about $3-25 each depending on length you need.