Problem In Connectivity

GovernmentSecurity.org > System Security > Networking Security / Firewall / IDS / VPN / Routers

ifhope

Sep 24 2004, 10:23 AM

I have 64Kbps link... with my ISP... with this 64K Link have approx. 15 clients/PCs connected via LAN... which have their own static Internet IPs...

from few days... PC's can't browse websites using direct connection... Gateway (router Cisco 2500) is working fine and then ISP DNS servers are working fine also... but no web browsing... but some of pages are opening like google, yahoo which are common... but other websites are not opening...

if i change the perference / options of the browser and set any International proxy, it begin browse websites...

Now if you ppl have any idea what is the problem... keep in mind... my router configuration is not changed from 6 months before this problem arise and after this problem i check my router configuration but there is no change...

I recofigure the router many time but the problem is same...

one more thing... MSN, Yahoo messenger and ICQ are working fine without proxy on clients...

Kindly help me... thx

SgtRush

Sep 30 2004, 01:27 PM

Assumptions.
1. You can still get to the web sites using an international proxy.

Lets start with verifying your DNS servers are really working.
1. Either ping or use nslookup to resolve a web site you are unable to browse to. If it resolves to a valid IP address go to 2. If it doesn't you have a DNS server issue.
2. Ping the IP address it resolved to. If you get a reply go to 3. If it doesn't there is a routing issue and its out of your hands.
3. Telnet to the resolved ip address on port 80. We are verifying that an HTTP service is running at this point. I forget what the command is to get the banner but I am sure someone else will gladly throw that info in for me. If the connection does not fail then a web service is running on that IP. Honestly if you get this far then everything should work. If it still doesn't then there is other pertinent information that you didn't provide in the initial post. Let me know if this helped and I hope you resolve your connectivity issues soon.

Sarge

macman

Sep 30 2004, 08:51 PM

Hi,

Try opening
64.236.16.84 (www.cnn.com)
66.102.9.99 (www.google.com)
in a browser on a client's PC.

If google works by (one of) it's I.P. addresses, but cnn doesn;t it could very well be an MTU issue.

ifhope

Oct 1 2004, 09:06 AM

thx guy... problem solved... it's DNS resolv problem... and just get solved on ISP end... thx again all of you...

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Help - Search - Member List - Calendar Full Version: Problem In Connectivity GovernmentSecurity.org > System Security > Networking Security / Firewall / IDS / VPN / Routers ifhope Sep 24 2004, 10:23 AM I have 64Kbps link... with my ISP... with this 64K Link have approx. 15 clients/PCs connected via LAN... which have their own static Internet IPs... from few days... PC's can't browse websites using direct connection... Gateway (router Cisco 2500) is working fine and then ISP DNS servers are working fine also... but no web browsing... but some of pages are opening like google, yahoo which are common... but other websites are not opening... if i change the perference / options of the browser and set any International proxy, it begin browse websites... Now if you ppl have any idea what is the problem... keep in mind... my router configuration is not changed from 6 months before this problem arise and after this problem i check my router configuration but there is no change... I recofigure the router many time but the problem is same... one more thing... MSN, Yahoo messenger and ICQ are working fine without proxy on clients... Kindly help me... thx SgtRush Sep 30 2004, 01:27 PM Assumptions. 1. You can still get to the web sites using an international proxy. Lets start with verifying your DNS servers are really working. 1. Either ping or use nslookup to resolve a web site you are unable to browse to. If it resolves to a valid IP address go to 2. If it doesn't you have a DNS server issue. 2. Ping the IP address it resolved to. If you get a reply go to 3. If it doesn't there is a routing issue and its out of your hands. 3. Telnet to the resolved ip address on port 80. We are verifying that an HTTP service is running at this point. I forget what the command is to get the banner but I am sure someone else will gladly throw that info in for me. If the connection does not fail then a web service is running on that IP. Honestly if you get this far then everything should work. If it still doesn't then there is other pertinent information that you didn't provide in the initial post. Let me know if this helped and I hope you resolve your connectivity issues soon. Sarge macman Sep 30 2004, 08:51 PM Hi, Try opening 64.236.16.84 (www.cnn.com) 66.102.9.99 (www.google.com) in a browser on a client's PC. If google works by (one of) it's I.P. addresses, but cnn doesn;t it could very well be an MTU issue. ifhope Oct 1 2004, 09:06 AM thx guy... problem solved... it's DNS resolv problem... and just get solved on ISP end... thx again all of you... This is a "lo-fi" version of our main content. To view the full version with more information, formatting and images, please click here.