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VMWare – Guest cannot browse Internet

I think I figured it out. It isn’t related to SLlinux, nor to port 443, nor to VMWare and the FC5 port directly, but a combination of the Fedora port and VMware settings. It is related to the MTU setting consistancy between the virtual machine, FC5 and the site in question. For some reason the FC5 was set to 1492 and not 1500 as set under FC3. For this reason some of the HTTPS sites, I assume, require 1500 mtu. All I did was set Fedora’s eth0’s MTU setting to 1500 (ip link set eth0 mtu 1500) and it works fine. Weird. I could be wrong, but I think that was the problem. At least now it works. I got this hint from the guys at Fidelity. They thought it was unrelated, but apparently it is.

Maximum Transmission Unit(MTU), the largest physical packet size, measured in bytes, that a network can transmit. Any messages larger than the MTU are divided into smaller packets before being sent.By optimizing the MTU setting you can gain substantial network performance increases, especially when using dial-up modem connections.

Default MTU Size for Different Network Topology

Network MTU(Bytes)
16 Mbit/Sec Token Ring 17914
4 Mbits/Sec Token Ring 4464
FDDI 4352
Ethernet 1500
IEEE 802.3/802.2 1492
X.25 576

To change the MTU of an interface on GNU/Linux, you just need to use ifconfig command to do so, like this for example

sudo ifconfig eth0 mtu 1492

To change it permanently on Debian, put it in the /etc/network/interfaces file .where almost all network parameters are found. To do this, just add a line mtu to the definition of your interface and save the file.

sudo gedit /etc/network/interfaces


iface eth0 inet static
mtu 1492

Daiup Users

For dialup users: the Maximum Transmission Unit (MTU) value can be changed within the file