On Apr 22, 2005, at 10:07 PM, [EMAIL PROTECTED] wrote:
Is the "trick" that the kernel makes packets destined *for* 127.0.0.0/8 appear to have come *from* 127.0.0.0/8?? I guess you couldn't have sending and receiving ports be the same then because then an app would be sending something to *itself* right?? That wouldn't make sense right?
Well, like any other IP address, services listen at predetermined ports even on 127.0.0.1. named listens on UDP/53, ssh on TCP/22, etc. If I do "slogin localhost", the source port used by the SSH client program is chosen the same way it would be as if I were logging in to sparkplug.kernel-panic.org, according to the design of the IP stack. The destination port is 22.
Most services these days don't send their packets from well-known ports, which actually used to be the norm (DHCP, BIND, RPC and others did this). So, I think it's not so much a problem as you might be imagining.
Gregory
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