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6

The endpoints of TCP connections are instantiated in software through a construct known as a socket. An instance of a TCP socket is defined by the source IP address, source port number, destination address and destination port number. If any of these parameters change (e.g., a packet arrives with a different source address), then then the software will ...


3

Ethernet interfaces on hosts, switches, routers, etc. will detect corrupted frames and drop them. Routers will also look at the IPv4 Header Checksum (IPv6 does not have this) to see if a packet header is corrupt, and drop the packet if it is. Hosts will look at the transport protocol to see if it is corrupt for those transport protocols that have a ...


2

Without looking at the packet-capture, network architecture etc. etc. it is a very hard question to answer. You can't really make a policy or anything that would drop frames (since they are routing at Layer 2 in the OSI model). However there are some things that could be going on: Broadcast storm - There could be a switch that is uplinking to another switch ...


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The only real problems are the ones you create. All the hosts will be able to talk to each other, and the internet via their respective gateway. Problems arise when you configure a router to send traffic to a host that does not use it as the gateway. For example, if there's a NAT rule from WAN2 to host1 (1.1). That will not work because the traffic will not ...


2

How do routers. switches, bridges and hubs deal with corrupted data? Frames and packets failing the integrity test (by FCS or header checksum) are dropped. By data corruption I mean frame/packet corruption, we can stick to the corruption due to a collision for simplicity. A collision fragment is not considered a corrupt frame, it is always dropped. ...


2

In summary, my question is: do each interface in a router have independent ip address/network[...]? Yes. Each interface on a router has an address on each separate network. In your example, you have two separate routers on two separate networks. As you've described them, they are independent of each other.


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Wi-fi requires two-way communication, so yes, proper operation depends on the transmit power and receiver sensitivity of both the mobile station and access point.


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What issues can occur when two routers are set to the same subnet (no cascading, both cable connected to the same switch)? None. Each client uses its default gateway. You could also add entries to their routing tables, making them use both gateways depending on the destination.


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I wonder if a device that handles this packet can modify the ip address before forwarding it to the final destination? Any node forwarding the packet can - in theory - modify anything in it. NAT routers translate between public and private addresses routinely. not so likely that the ISP or another node before the final destination would do so. Your ISP ...


1

My ip address is specified in the ip packet sent to the next node. I wonder if a device that handles this packet can modify the ip address before forwarding it to the final destination? That is called NAT (Network Address Translation), and it is very common. For example, nearly all home networks use Private IPv4 addressing that cannot be seen on the ...


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You cannot route any traffic destined to any address in the 127.0.0.0/8 block on an external network. Any address in the 127.0.0.0/8 block can never appear anywhere on any network, nor can any address in that block be used as a source or destination address for packets outside the host. The goes back at least as far as RFC 990, ASSIGNED NUMBERS: The ...


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