What will happen if a router received a ICMP packet with TTL 0?

What are two things will happen if a router receives an icmp packet which has a ttl value of 1 and the destination host is several hops away?

1.The router will discard the packet. 2.The router will send a time exceeded message to the source host.

What is the minimum maximum size of ICMP packet?

The minimum size of an ICMP packet is 8 bytes, which includes the 8-byte ICMP header without any additional data. The maximum size of an ICMP packet is 65,535 bytes, which includes the maximum payload that can be carried within an IPv4 packet.

Why is it that an ICMP packet does not have source and destination port?

Because ICMP is on the network layer

What are the main functions of icmp?

Internet Control Message Protocol (ICMP), documented in RFC 792, is a required protocol tightly integrated with IP. ICMP messages, delivered in IP packets, are used for out-of-band messages related to network operation or mis-operation. Of course, since ICMP uses IP, ICMP packet delivery is unreliable, so hosts can't count on receiving ICMP packets for any network problem. Some of ICMP's functions are to: * Announce network errors, such as a host or entire portion of the network being unreachable, due to some type of failure. A TCP or UDP packet directed at a port number with no receiver attached is also reported via ICMP. * Announce network congestion. When a router begins buffering too many packets, due to an inability to transmit them as fast as they are being received, it will generate ICMP Source Quenchmessages. Directed at the sender, these messages should cause the rate of packet transmission to be slowed. Of course, generating too many Source Quench messages would cause even more network congestion, so they are used sparingly. * Assist Troubleshooting. ICMP supports an Echo function, which just sends a packet on a round--trip between two hosts. Ping, a common network management tool, is based on this feature. Ping will transmit a series of packets, measuring average round--trip times and computing loss percentages. * Announce Timeouts. If an IP packet's TTL field drops to zero, the router discarding the packet will often generate an ICMP packet announcing this fact. TraceRoute is a tool which maps network routes by sending packets with small TTL values and watching the ICMP timeout announcements.By far the most common use of icmp is ping.

How traceroute works?

The "traceroute" program uses ICMP messaging and the time to live (TTL) field in the IP header. It works by sending a packet to the intended host with a TTL value of 1. The first router will send back the ICMP "time exceeded" message to the sending host. Then the traceroute program will send a message with a TTL of 2, then 3, etc. This way it will get information about each router using the information received in the ICMP packets. To get information about the receiving host, the message is sent to a port that is not likely to be serviced by that host. A ICMP "port unreachable" error message is generated and sent back.

What is the size of the smallest icmp packet?

64 Bytes.

What packet is used in ping command?

Packet Internet Groper(PING) is an Internet Control Message Protocol(ICMP) request packet for it's working. ICMP packets are used to check networks are live or not. -- By MYNarutoAnime ----

What protocol sends redirects to an originating router?

ICMP

What steps are taken when forwadin an icmp packet?

For each router, the following steps occur: 1) The "access-group in" command is checked on the interface, and discards the packet if the rule tells it to do so. 2) The "TTL" field is decreased by 1. 3) If TTL is now 0, the router discards the packet and sends a reply packet back to the sender. 4) The packet's IP address is compared to the routing table to determine the next hop of the packet. 5) The router advises if the network or host is unreachable due to a down interface or no known route. 6) The router sends the packet to the outgoing interface's queue to be sent to the next hop. 7) The "access-group out" command is checked on the interface, and discards the packet if the rule tells it to do so. 8) The router sends the packet to the next hop.

What is the maximum size of an IP packet carrying an ICMP packet?

The maximum for any IP packet via ethernet is limited to a maximum of 1508 characters. ICMP packets are typically small but can be configured to use any amount of characters up to the maximum size of a packet.

What protocol allows hosts to exchange messages to indicate problems with packet delivery?

ICMP The Internet Message Protocol (ICMP) allows hosts to exchange messages to indicate the status of a packet as it travels through the network.

Why the ttl change in the same ping?

The TTL (Time to Live) value in a ping packet decreases by 1 each time it passes through a router. This helps prevent packets from circulating endlessly in a network. When a TTL reaches 0, the router discards the packet and sends an ICMP Time Exceeded message.