Timeline for Connecting to IP 0.0.0.0 succeeds. How? Why?
Current License: CC BY-SA 4.0
16 events
| when toggle format | what | by | license | comment | |
|---|---|---|---|---|---|
| Nov 19, 2022 at 13:54 | history | edited | Stephen Kitt | CC BY-SA 4.0 | Such packets go out over the loopback interface. |
| Nov 19, 2022 at 13:44 | history | edited | Stephen Kitt | CC BY-SA 4.0 | Fix the explanation, many many thanks to correabuscar for the details. |
| Nov 18, 2022 at 14:39 | history | edited | Philip Couling | CC BY-SA 4.0 | Made the RFC reference more prominent to give better context to the statement |
| Oct 7, 2021 at 7:34 | history | edited | CommunityBot | replaced https://tools.ietf.org/html/rfc with https://www.rfc-editor.org/rfc/rfc | |
| Mar 23, 2019 at 15:45 | comment | added | Tim | Does 0.0.0.0 have two completely different meanings? A process specifies its own unknown address to another process not in the same host. A process specifies that it is listening on all the addresses on the local host? | |
| Mar 23, 2019 at 9:08 | comment | added | Stephen Kitt | Where did I say a client can’t use 0.0.0.0? I’ve explained what happens when a client connects to 0.0.0.0, which implies that it is possible (even though theory says it isn’t). 0.0.0.0 is used as a source address when the real source address isn’t known, e.g. for DHCP requests. | |
| Mar 22, 2019 at 20:48 | comment | added | Tim | So you mean a client can't use 0.0.0.0 as destination. How can it be used as a source? | |
| Mar 22, 2019 at 20:31 | comment | added | Stephen Kitt | I’m not sure how to clarify. When MySQL listens on 0.0.0.0, that corresponds to the second paragraph of my answer. A client can connect to the server using any valid address for the server, reachable by the client; but not using 0.0.0.0, unless the server is on the same system as the client. | |
| Mar 22, 2019 at 20:08 | comment | added | Tim | Could you clarify what you mean by "it isn’t valid as a destination address, only as a source address"? When mysql server listens at 0.0.0.0, is the address destination or source? Is it not the destination of a request sent from a mysql client? | |
| Jan 27, 2018 at 19:11 | comment | added | TOOGAM | @Dezza No, localhost is 127.0.0.1. 127.0.0.0/8 (as you say, a.k.a. 127.0.0.0 through 127.255.255.255) is loopback with most equipment, e.g. documented by RFC 5735 page 4. (Interestingly, some Cisco equipment can assign loopback to any address, but defaults to not supporting loopback at all. Not that this is likely to affect other equipment on the network.) However, localhost is a name, typically pointing to just to a single address which is 127.0.0.1, and commonly implemented by using a "hosts" file. So I disagree with your attempted correction. | |
| Jan 27, 2018 at 15:05 | comment | added | Dezza | @rexkogitans localhost is not a single address, but any address in the range 127.0.0.0/8 - i.e. any address from 127.0.0.0 to 127.255.255.255 | |
| Jan 27, 2018 at 11:21 | comment | added | rexkogitans | localhost is a single address, mostly 127.0.0.1, while 0.0.0.0 means all addresses on this host. | |
| Jan 27, 2018 at 9:23 | comment | added | Criggie | To extend this answer a little - it means "any IP address on this system, including IPs that have been added after the listening process started" | |
| Jan 26, 2018 at 20:34 | vote | accept | erikbstack | ||
| Jan 26, 2018 at 16:36 | history | edited | Stephen Kitt | CC BY-SA 3.0 | Typo. |
| Jan 26, 2018 at 16:21 | history | answered | Stephen Kitt | CC BY-SA 3.0 |