Ssh
埠（作為通信連接端點）在 SSH 埠轉發中屬於哪些程序？
(1) 遠端轉發：
-R [bind_address:]port:host:hostport Specifies that the given port on the remote (server) host is to be forwarded to the given host and port on the local side. This works by allocating a socket to listen to port on the remote side, and whenever a connection is made to this port, the connection is forwarded over the secure channel, and a connection is made to host port hostport from the local machine. Port forwardings can also be specified in the configuration file. Privileged ports can be forwarded only when logging in as root on the remote machine. IPv6 addresses can be specified by enclosing the address in square brackets. By default, the listening socket on the server will be bound to the loopback interface only. This may be overridden by specifying a bind_address. An empty bind_address, or the address ‘*’, indicates that the remote socket should listen on all interfaces. Specifying a remote bind_address will only succeed if the server's GatewayPorts option is enabled (see sshd_config(5)). If the port argument is ‘0’, the listen port will be dynamically allocated on the server and reported to the client at run time. When used together with -O forward the allocated port will be printed to the standard output.
hostport為在目標上執行的目標程序指定一個連接端點host。是
port連接端點
- 在 SSH 伺服器程序中，或
- 在與 SSH 伺服器在同一源主機上執行的程序中，並希望通過將自身附加到 SSH 隧道來使用
port？（我的猜測是後者）
(2) 對於本地轉發：
-L [bind_address:]port:host:hostport Specifies that the given port on the local (client) host is to be forwarded to the given host and port on the remote side. This works by allocating a socket to listen to port on the local side, optionally bound to the specified bind_address. Whenever a connection is made to this port, the connection is forwarded over the secure channel, and a connection is made to host port hostport from the remote machine. Port forwardings can also be specified in the configuration file. IPv6 addresses can be specified by enclosing the address in square brackets. Only the superuser can forward privileged ports. By default, the local port is bound in accordance with the GatewayPorts setting. However, an explicit bind_address may be used to bind the connection to a specific address. The bind_address of “localhost” indicates that the listen‐ ing port be bound for local use only, while an empty address or ‘*’ indicates that the port should be available from all interfaces.
hostport為在目標上執行的目標程序指定一個連接端點host。是
port連接端點
- 在 SSH 客戶端程序中或
- 在與 SSH 客戶端在同一源主機上執行的程序中，並希望通過將自身附加到 SSH 隧道來使用
port？（我的猜測是後者）
(3) 對於 SOCKS 代理：
-D [bind_address:]port Specifies a local “dynamic” application-level port forwarding. This works by allocating a socket to listen to port on the local side, option‐ ally bound to the specified bind_address. Whenever a connection is made to this port, the connection is forwarded over the secure channel, and the application protocol is then used to determine where to connect to from the remote machine. Currently the SOCKS4 and SOCKS5 protocols are supported, and ssh will act as a SOCKS server. Only root can forward privileged ports. Dynamic port forwardings can also be specified in the configuration file. IPv6 addresses can be specified by enclosing the address in square brackets. Only the superuser can forward privileged ports. By default, the local port is bound in accordance with the GatewayPorts setting. However, an explicit bind_address may be used to bind the connection to a specific address. The bind_address of “localhost” indicates that the listening port be bound for local use only, while an empty address or ‘*’ indicates that the port should be available from all interfaces.是
port連接端點
- 在 SSH 客戶端程序中，
- 在 SSH SOCKS 伺服器中，或
- 在與 SSH 客戶端在同一主機上執行的程序中，並希望通過連接來使用 SOCKS 伺服器
port？（我的猜測是第二個。我猜它不是第一個，因為 SSH 客戶端有自己的預設埠。我不確定第三個）
這些草圖應該可以幫助您回答所有問題：https ://unix.stackexchange.com/a/118650/121504
但是要明確回答您的問題：
- 對於遠端轉發：
port是 SSH 伺服器中的連接端點。 2. 對於本地轉發：
port是 SSH 客戶端程序中的連接端點 3. 對於 SOCKS 代理：
port是 SSH 客戶端程序中的連接端點但更多視覺解釋實際上是上面連結的草圖。但總結一下：
第一個埠（對於 SOCK 代理是唯一的）始終是您將使用下一步連接的空閒埠。****另一個埠是執行現有服務的埠。
編輯：
如果我了解真正的問題是使用
lsof. 您的埠在我的範例中12345：對於遠端轉發：
[local ] $ ssh -R 12345:localhost:22 remote [remote] $ lsof -P | grep 12345 sshd 27772 root 7u IPv6 1304283702 0t0 TCP localhost:12345 (LISTEN) sshd 27772 root 8u IPv4 1304283703 0t0 TCP localhost.localdomain:12345 (LISTEN)對於本地轉發：
[local] $ ssh -L 12345:localhost:22 remote [local] $ lsof -p $(pidof ssh) -P | grep 12345 ssh 6779 jakuje 4u IPv6 146565 0t0 TCP ip6-localhost:12345 (LISTEN) ssh 6779 jakuje 5u IPv4 146566 0t0 TCP localhost:12345 (LISTEN)對於動態埠轉發：
[local] $ ssh -D 12345 root@dta3.com [local] $ lsof -p $(pidof ssh) -P | grep 12345 ssh 11388 jakuje 4u IPv6 173537 0t0 TCP ip6-localhost:12345 (LISTEN) ssh 11388 jakuje 5u IPv4 173538 0t0 TCP localhost:12345 (LISTEN)