A firewall generally works at layer 3 and 4 of the OSI model. Layer 3 is the Network Layer where IP works and Layer 4 is the Transport Layer, where TCP and UDP function.
Many firewalls today have advanced up the OSI layers and can even understand Layer 7 - the Application Layer.
it may be network layer or transport layer.. it depends on the design of the firewall.. also depends on the requirement specification..
The Hyper Text Transfer Protocol (HTTP) works on Layer 7 on the Application layer of the OSI Model.
Firewalls control all incoming and outgoing connections and if it's required block it or limit. Firewalls work with software, but not with accounts. Access lists control permissions and read-write rights for users (accounts) with certain username and password (if required).
layer 3 layer 3 Switch/ Bridges / Hubs works at layer 2 as they utilizes MAC address to communicate. However i aggree above stated answer as there are some layer three switches that work at Layer3 i.e. Network Layer. Dhruv
TELNET operates at Application Layer in TCP/IP Model. It's an Application to establish a connection to TCP Port Number 23, where a Telnet server application (telnetd) is listening.
A firewall generally works at layer 3 and 4 of the OSI model. Layer 3 is the Network Layer where IP works and Layer 4 is the Transport Layer, where TCP and UDP function. Many firewalls today have advanced up the OSI layers and can even understand Layer 7 - the Application Layer.
a) How is an application-layer gateway (ALG) different from a firewall?
it may be network layer or transport layer.. it depends on the design of the firewall.. also depends on the requirement specification..
The default Windows Firewall also monitors the Application layer
firewall, router,layer 3 switches and i approve that answer ! NO! In general the firewall is a layer 4 device, it traffics filter incoming and outgoing ports. It uses the function of TCP and UCP. However a Firewall can also be a layer 3 device as in internal firewall in a router. Also a switch is a layer 2 device unless your talking about a Router switch.
circuit-level gateway
Stateful firewall checks more than just the ACK flag;it inspects the sequence numbers to ensure the correct state of the TCP session.
Network Layer
transport layer
physical layer
fourth layer
No. Hub works only on first layer. On second layer only swithc/bridge works on second layer of OSI model.