If a GPRS router shows the link is up but can't be able to access any web page, what may be the problem? And what is the solution ?

Problem of the GPRS provider

or Routers routing table wrongly

or Access-list blocking the traffic

or URL filtering being applied

or internal routing problem (Vlan routing misconfigured)

or Switching problem (ports, vlans, spanning-tree, etherchannels, etc.)

or cabling/physical problems

The solution would be to follow each od this itens, check the status and config, to find what is causing the no web access.

The followwing are the problems which may cause. 

Problem of the GPRS provider

or Routers routing table wrongly

or Access-list blocking the traffic

or URL filtering being applied

or internal routing problem (Vlan routing misconfigured)

or Switching problem (ports, vlans, spanning-tree, etherchannels, etc.)

or cabling/physical problems

Sloution 

Ping an Internet address

1. Open Window Command Line Prompt 
2. At a prompt type, ping 45.79.151.23

Response from IP

If you receive a response from the IP address, but not the domain computerhope.com, you are encountering a problem with your DNS

Make sure that your DNS and ISP service provider Ip addresses are same 

No response from IP

If you get no response from the IP address and the computerhope.com address, nothing is being sent over your network. If your are on a home network, unplug the power to your router and broadband modem.

Problem can be any of the mentioned below:

1. DHCP issue

2. NAT or PAT issue

3-Package Information & details

problem are:

1. dns issue

2. routing, access list or NATing issue

the solutions are

1. check icmp of dns

2, need to check nslookup from  device

2. add dns server ip in network adapter

3. also need to check in browser connection setting proxy is enable or disable it depends on router configuration

3.also check NAT & routing

Noted: most of the times are happenig DNS issue

Best techninque to resolve Computer Network Errors is to Checkup the Source Hardware first and then the Link/medium e.g Ethernet and then the Destination Hardware. Then have some work on Sofwatre Involved.

Wrong Roueting Table Entry in router and the Access-List is deniying the service.