These changes cause narrowing of the lumbar spinal canal which is known as spinal stenosis. Spinal stenosis is like the lime build-up on the inside of a garden hose. Over time, it narrows the diameter of the hose, just as spinal stenosis narrows the spinal canal.
SMTP Protocol: The SMTP (Simple Mail Transfer Protocol) protocol is used by the Mail Transfer Agent (MTA) to deliver your eMail to the recipient's mail server. The SMTP protocol can only be used to send emails, not to receive them.
The e-mail client runs on a personal computer in someone's home network, which is set up using the Ethernet protocol. The link layer now is that Ethernet network. The IP packets that this computer transmits, are added as payload to Ethernet packets (called frames) that are transmitted over the local network to the ADSL modem that connects the local network to the provider.