When I ran ping tests, I found I could ping other systems and get responses and could get a response to a ping to the loopback address, 127.0.0.1, but I got no response when trying to ping the system's IP address, which in this case was 192.168.1.106. And when I tried establishing a connection to the SMTP or POP3 ports on a mail server with telnet, I got "connect failed" messages.
telnet 192.168.1.53 110
Connecting To 192.168.1.53...Could not open connection to the host, on port 110:
Connect failed
telnet 192.168.1.53 25
Connecting To 192.168.1.53...Could not open connection to the host, on port 25:
Connect failed
I also couldn't connect to an FTP server on the LAN with ftp nor to a web server on the LAN by using telnet to attempt to connect to port 80. Nor could I connect to any web server by that method.
When I booted the system, which was a Windows XP Professional system with Service Pack (SP) 1 installed, into safe mode with networking support, I was able to run Internet Explorer and all of the above tests that failed when the system was booted normally now worked.
I've seen similar problems on systems caused by adware/spyware. But I was also getting a message from Symantec AntiVirus Corporate Edition 9 on the system that its auto-protect feature was no longer working. And I could not update Symantec AntiVirus even in safe mode with networking support. I even downloaded the latest Symantec virus definitions and tried manually updating the antivirus program, but the virus definitions remained at the prior version.
Since I thought some virus, trojan, adware/spyware, or other malware might be causing the problem, I installed the free antivirus program ClamWin. That program didn't detect anything significant, so I also tried several free online virus scanners. I also updated Microsoft AntiSpyware, Ad-aware SE Personal, Bazooka Spyware Scanner, and Spybot Search & Destroy, which were already on the system, and then scanned the system with those. Though I found remnants of some adware/spyware, there was nothing that I thought would cause the problem I was encountering nor did removing what was found eradicate the problem.
I installed Windows XP Service Pack 2, which I had to install in safe mode. After I rebooted, I was able to open Internet Explorer and access websites and access the mail server with telnet, as above, as well. But only for a brief time. Within several minutes the orginal problem was back.
I've seen loss of Internet access and other problems when adware/spyware inserts itself at the Layered Service Provider (LSP) level. But when I checked the LSP software, I found nothing suspicious
I had Windows XP's built-in firewall disabled and I thought I had disabled
Norton Internet Security 2002's firewall early on in the troubleshooting
process to ensure it wasn't the cause of the problem. I booted into safe
mode and renamed the directory where it was located,
C:\Program Files\Norton Internet Security and then rebooted into
the normal mode of Windows XP. I then didn't see any of the Norton Internet
Security services running when I checked the running services by going to
Start, Control Panel, Administrative Tools, Services
. Nor did I see any processes associated with it when I ran the Task Manager.
I even installed
The
Ultimate Troubleshooter™ to check for suspcious tasks or services, but
didn't see anything assocated with Norton Internet Security or anything else
that would account for the problem.
But somehow, despite the fact that I had renamed the Norton Internet Security directory and rebooted afterwards and didn't see any services or tasks running associated with it afterwards, it was still blocking Internet access and the pings to the system's own IP address. Because when I later looked at it again as the possible source of the problem by putting the directory name back to what it was and restarting the system, the problem with Internet Explorer not starting was gone and I could access the mail server. I still couldn't ping the system's own IP address, but when I right-clicked on the Norton Internet Security icon in the system tray (it's a green and blue globe icon) and chose "disable", I could then ping the system's IP address as well as other IP addresses.
I don't know why it may have originally started keeping Internet Explorer from opening and prevented Internet access. Perhaps I did remove something that was causing a problem for Norton Internet Security when I ran the antivirus and antispyware scans. But I worked on the system over the course of several days before I finally looked at Norton Internet Security as a possible source of the problem again. When I got it working again, the problem was resolved. I could access websites then and the LiveUpdate feature of Symantec AntiVirus worked again.
References:
Created: August 13, 2005