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Ping Question
If the Internet companies were able to ping internet users before they sent packets to a connection. If they didn't get a hit they would just drop the call. Wouldn't it greatly improve security? I know in Russia they block all udp.
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Usually there is no need to do such a thing. Most connections use TCP/IP "sockets" which are bi-directional and persistent. Once the socket has been established, there's no further verification required before sending traffic through it.
"Russia" certainly does not "block all UDP," and even "the Great Firewall of China™" has holes in it. None of this has anything to do with security. The only way to provide security for a TCP/IP or UDP connection is to encrypt the traffic. "Ping" (ICMP ECHO ...) is simply a very lightweight way to see if an IP-address is occupied ... i-f the computer in question is programmed to respond to it. |
Also because most internet users are behind a NAT, so the only info the "internet company" has is the socket which is on the tcp session.
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ok answer me this
Does the IP header contain the source address? In what protocal is it dropped?
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IP4 Header diagram
As we all know a ip4 header diagram contains both source and destination address. Ping only works on a valid ip address. If it is fake it doesn't go through. Ping may be trivial but it does work. A local switch could be programmed to ping all packets on arrival and drop any invalid? If this doesn't work how could it work?
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correction
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This still doesn't tell me why using ping wouldn't work. |
Interesting 'study'. I'm guessing NAT is a key piece, where 'many' IP are 192.168.1.2
I was trying to come up with 'good' web-research keywords, but I hit this tangent via: use ping to verify valid nat source IP bogus|spoof Can anyone advise on a better web-research ...? Thanks! p.s. packet filtering ? http://wpollock.com/AUnixSec/IptablesOverview.htm |
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