Polipo is a free simple, small and fast caching web proxy. Polipo can be used out of the box and can support a single user on a computer or many computers on a network and can even support higher number of users on a bigger network.
Features of Polipo WebProxy are
Maximum Segment Size (MSS) value advertised by a Server or a System is the preffered size of the segment that it can receive. For an standard packet this is equivalent to the Maximum Transmission unit (MTU) – 40bytes (standard TCP/IP overhead of 40 bytes [20+20]). This is the value that the server advertises and not what we can transmit.
If the MTU is 1500 bytes then the MSS will be 1460 bytes.
The Maximum Transmission Unit (MTU) can be set/modified in real time on Redhat Enterprise Linux or can be set force the value at boot time.
The MTU in simple terms is the maximum size of a packet that can be sent on a Network Interface card. The default MTU size is 1500 bytes.
Advanced Subnet Calculator from SolarWind is a simple but powerful easy to use Subnet Calculator for Windows.
Advanced Subnet Calculator can perform
whois lookups for hostnames and Domain Names
IPWhois Lookup for the provided IP Address
Classful Subnet Calculator
Claseless Inter-Domain Routing (CIDR) Calculator
Address Generator for a given IP Address and Subnet Mask
We discussed NAT Overloading in the Part-1 of our Cisco IOS NAT configuration here
Here, we will configure a Static NAT on Cisco IOS Routers. Static NAT is rather straightt forward as it is a one to one NATing between IP addresses as against the NAT Overloading or the Dynamic NAT where the IP addresses from the inside are NATed to a pool of IPs.
Gateway Load Balancing Protocol (GLBP) as the name implies can be used to configure Gateway redundancy between a group of routers and at the same time load balance the traffic across all of them. GLBP is similar to the High availability protocols Hot Standby Redundancy Protocol (HSRP) & Virtual Router Redundancy Protocol (VRRP) except for the load balancing capabilities wherein HSRP and VRRP, the standby routers are configured for redundancy and act as standby only and become active only when the active router fails.
The advantage of GLBP is it provides load balancing over multiple routers (gateways) using a single virtual IP address and multiple virtual MAC addresses. The forwarding load is shared among all routers in a GLBP group rather than being handled by a single router while the other routers stand idle. Each host is configured with the same virtual IP address, and all routers in the virtual router group participate in forwarding packets. GLBP members communicate between each other through hello messages sent every 3 seconds to the multicast address 224.0.0.102, User Datagram Protocol (UDP) port 3222 (source and destination).
Virtual Private Network (VPN) is a network which uses a shared network infrastructure (Internet) which allows a secure access between two networks or securely connects a remote user to his corporate network.
Let's check out here how to configure a Site to Site VPN using a Pre-shared Key in Cisco Routers running Cisco IOS