office workstations can no longer access Experts-exchange.com
As of about two weeks ago non of the workstations non of the office workstations can access Experts-exchange.com [64.156.132.140]. I've removed all firewall / AV software from one workstation to eliminated that as a possible reason. I can ping / traceroute to Exports-exchange.com. I was working with local ISP on connection issues, but this started happening about 2 day after dealing with qwest. The only config change was going from PPPoE to PPPoA on the dSL modem. I have a group of static IPs going to the Atec gt701 Modem/router. All traffic routes to Cisco 1800 series router. I have Windows 2k3 standard servers handling DNS and DHCP on the LAN.
Raheem05
if you do nslookup on the client pc's what does experts-exchange.com resolve as?
ASKER
the ip address you see above: 64.156.132.140
So the problem is not with address resolution which is a pity as that would be the easy thing to look at :o)
I take it that if you put the IP address (64.156.132.140) into your browser it does not work (i.e.: a timeout)?
I take it that pinging the IP address works okay?
If this is true that means that ICMP echo (a.k.a. ping) is passing thought the entire network path, while http is not. Which means something is blocking http somewhere on the network path.
Do you use a proxy server? If you do, check the proxy server.
What about edge firewalls? Check them (you may have already done so).
What you need to do to troubleshoot is to do a trace route over TCP on port 80 (which is http). This is quite easy with the built in tools in most Linux distributions, not so easy with Windows (without external tools - like NetScan Tools). Perhaps get a copy of the open source tcptrace from http://tracetcp.sourceforge.net/, but you'll probably need to compile it and so on. Alternatively, try http://goheer.com/products/tcptraceroute/ - sorry, don't use Windows prefer network orientated computers :o)
Hope this helps.
I take it that if you put the IP address (64.156.132.140) into your browser it does not work (i.e.: a timeout)?
I take it that pinging the IP address works okay?
If this is true that means that ICMP echo (a.k.a. ping) is passing thought the entire network path, while http is not. Which means something is blocking http somewhere on the network path.
Do you use a proxy server? If you do, check the proxy server.
What about edge firewalls? Check them (you may have already done so).
What you need to do to troubleshoot is to do a trace route over TCP on port 80 (which is http). This is quite easy with the built in tools in most Linux distributions, not so easy with Windows (without external tools - like NetScan Tools). Perhaps get a copy of the open source tcptrace from http://tracetcp.sourceforge.net/, but you'll probably need to compile it and so on. Alternatively, try http://goheer.com/products/tcptraceroute/ - sorry, don't use Windows prefer network orientated computers :o)
Hope this helps.
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ASKER
I was also told people were receiving "451 Timeout waiting for client input" errors when sending mail to my email server.