quoted from
http://www.ChicagoTech.net
Can't access some web sitesSymptoms: 1) If you're using MS ICS or Windows
server as router to access the Internet, your clients may not be able to
access certain web sites. However, the ICS host or the server doesn't have
this problem.
2) After installed a new router or cable modem replacing dial-up to access
the Internet, you can't access some web sites.
3) You also find that most web sites you can't access are block to ping or
they are security sites using HTTPS.
Causes: 1) The problem occurs because many web servers block ICMP messages
and the packets are dropped. As a result, the requested web site doesn't
load.
2) This problem is caused also by an incompatible MTU networking setting.
You may try to install the latest SP. If you use MS ICS, you may want to
configure all your Client computers to use the new, lower MTU as the default
for all Internet communication. To modify the MTU size, locate the following
registry key: HKEY_LOCAL_MACHINE\ SYSTEM\ CurrentControlSet\ Services\
Tcpip\ Parameters\ Interfaces. If you use a router like Cisco DSL Router,
you may want to adjusting the PPPoE MTU Size. For example, to adjusting the
PPPoE MTU Size on the Cisco DSL Router, do
interface ethernet0
no shut
ip address <ip address> <subnet mask>
ip adjust-mss 1452
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Robert Lin, MS-MVP, MCSE & CNE
Networking, Internet, Routing, VPN, Anti-Virus, Tips & Troubleshooting on
http://www.ChicagoTech.net
This posting is provided "AS IS" with no warranties.
