Python Webserver
Vamos a ver como lanzar un sencillo webserver con tan solo ejecutar un comando.
Esto puede ser muy util para comprobar rutas , paginas conexiones web etc.
Nota: No lo recomiento en un entorno produtivo de alto rendimiento.
El comando es facil: python3 -m http.server 13020
Donde 13020 es el puerto en el que quiero que escuche.
root@em50l:~# python3 -m http.server 13020 Serving HTTP on 0.0.0.0 port 13020 ...
Cuando un cliente se conecte veremos una linea con la conexion:
127.0.0.1 - - [06/Dec/2019 12:36:53] "GET / HTTP/1.1" 200 - 9.4.198.26 - - [06/Dec/2019 12:37:09] "GET / HTTP/1.1" 200 - ^C Keyboard interrupt received, exiting.
Comprobar que funciona. Probamos desde localhost:
jejo@em50l:~$ curl -kvs localhost:13020 * Trying ::1... * TCP_NODELAY set * connect to ::1 port 13020 failed: Connection refused * Trying 127.0.0.1... * TCP_NODELAY set * Connected to localhost (127.0.0.1) port 13020 (#0) > GET / HTTP/1.1 > Host: localhost:13020 > User-Agent: curl/7.52.1 > Accept: */* > * HTTP 1.0, assume close after body < HTTP/1.0 200 OK < Server: SimpleHTTP/0.6 Python/3.5.3 < Date: Fri, 06 Dec 2019 11:36:53 GMT < Content-type: text/html; charset=ascii < Content-Length: 1038 < <!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN" "http://www.w3.org/TR/html4/strict.dtd"> <html> <head> <meta http-equiv="Content-Type" content="text/html; charset=ascii"> <title>Directory listing for /</title> </head> <body> <h1>Directory listing for /</h1> <hr> <ul> <li><a href="test.html">test.html</a></li> </ul> <hr> </body> </html> * Curl_http_done: called premature == 0 * Closing connection 0
Apendice Depuracion tcpdum.
Si algo falla es bueno tener informacion tcpdump.
Paquetes/solicitudes que no entran, Respuestas que no salen etc….
Nos puede ayudar a detectar problemas con la red y con la comunicacion TCP/IP.
tcpdump -vvlnn inbound and dst port 13020 or outbound and src port 13020
Si tcpdump es incapaz de detectar el protocolo http tendremos que añadir -X para ver los datos.
tcpdump -vvlnnX inbound and dst port 13020 or outbound and src port 13020
Nota: el filtro es importante. (inbound and dst port 13020 or outbound and src port 13020)
ya que si nuestro servidor saldria mucho “ruido” que tendriamos que separar.
Aqui dejo una captura de trafico en la que se ven las peticiones y las respuestas HTTP:
root@em50l:# tcpdump -lnnAX -s256 " (outbound and src port 13020) or (inbound and dst port 13020)"
tcpdump: verbose output suppressed, use -v or -vv for full protocol decode
listening on venet0, link-type LINUX_SLL (Linux cooked), capture size 256 bytes
12:31:25.758796 IP 94.36.158.56.60270 > 172.16.20.130.13020: Flags [S], seq 494947881, win 27200, options [mss 1308,sackOK,TS val 291161489 ecr 0,nop,wscale 7], length 0
0x0000: 4500 003c 4550 4000 3906 1691 5f2e c61a E..<EP@.9..._...
0x0010: ac10 1482 eb6e 32dc 1d80 4e29 0000 0000 .....n2...N)....
0x0020: a002 6a40 979c 0000 0204 051c 0402 080a ..j@............
0x0030: 115a c591 0000 0000 0103 0307 .Z..........
12:31:25.758912 IP 172.16.20.130.13020 > 94.36.158.56.60270: Flags [S.], seq 3146976960, ack 494947882, win 14480, options [mss 1460,sackOK,TS val 3291355375 ecr 291161489,nop,wscale 7], length 0
0x0000: 4500 003c 0000 4000 4006 54e1 ac10 1482 E..<..@.@.T.....
0x0010: 5f2e c61a 32dc eb6e bb93 0ec0 1d80 4e2a _...2..n......N*
0x0020: a012 3890 2132 0000 0204 05b4 0402 080a ..8.!2..........
0x0030: c42e 18ef 115a c591 0103 0307 .....Z......
12:31:25.862847 IP 94.36.158.56.60270 > 172.16.20.130.13020: Flags [.], ack 1, win 213, options [nop,nop,TS val 291161608 ecr 3291355375], length 0
0x0000: 4500 0034 4551 4000 3906 1698 5f2e c61a E..4EQ@.9..._...
0x0010: ac10 1482 eb6e 32dc 1d80 4e2a bb93 0ec1 .....n2...N*....
0x0020: 8010 00d5 8742 0000 0101 080a 115a c608 .....B.......Z..
0x0030: c42e 18ef ....
12:31:25.862860 IP 94.36.158.56.60270 > 172.16.20.130.13020: Flags [P.], seq 1:85, ack 1, win 213, options [nop,nop,TS val 291161609 ecr 3291355375], length 84
0x0000: 4500 0088 4552 4000 3906 1643 5f2e c61a E...ER@.9..C_...
0x0010: ac10 1482 eb6e 32dc 1d80 4e2a bb93 0ec1 .....n2...N*....
0x0020: 8018 00d5 14a1 0000 0101 080a 115a c609 .............Z..
0x0030: c42e 18ef 4745 5420 2f6b 6b20 4854 5450 ....GET./kk.HTTP
0x0040: 2f31 2e31 0d0a 486f 7374 3a20 6861 7264 /1.1..Host:
0x0050: 2e6a 656a 6f2e 7077 3a31 3330 3230 0d0a jejo.pw:13020..
0x0060: 5573 6572 2d41 6765 6e74 3a20 6375 726c User-Agent:.curl
0x0070: 2f37 2e35 382e 300d 0a41 6363 6570 743a /7.58.0..Accept:
0x0080: 202a 2f2a 0d0a 0d0a .**....
12:31:25.862986 IP 172.16.20.130.13020 > 94.36.158.56.60270: Flags [.], ack 85, win 114, options [nop,nop,TS val 3291355479 ecr 291161609], length 0
0x0000: 4500 0034 1796 4000 4006 3d53 ac10 1482 E..4..@.@.=S....
0x0010: 5f2e c61a 32dc eb6e bb93 0ec1 1d80 4e7e _...2..n......N~
0x0020: 8010 0072 86e8 0000 0101 080a c42e 1957 ...r...........W
0x0030: 115a c609 .Z..
12:31:25.863949 IP 172.16.20.130.13020 > 94.36.158.56.60270: Flags [P.], seq 1:185, ack 85, win 114, options [nop,nop,TS val 3291355480 ecr 291161609], length 184
0x0000: 4500 00ec 1797 4000 4006 3c9a ac10 1482 E.....@.@.<.....
0x0010: 5f2e c61a 32dc eb6e bb93 0ec1 1d80 4e7e _...2..n......N~
0x0020: 8018 0072 4c33 0000 0101 080a c42e 1958 ...rL3.........X
0x0030: 115a c609 4854 5450 2f31 2e30 2034 3034 .Z..HTTP/1.0.404
0x0040: 2046 696c 6520 6e6f 7420 666f 756e 640d .File.not.found.
0x0050: 0a53 6572 7665 723a 2053 696d 706c 6548 .Server:.SimpleH
0x0060: 5454 502f 302e 3620 5079 7468 6f6e 2f33 TTP/0.6.Python/3
0x0070: 2e35 2e33 0d0a 4461 7465 3a20 5375 6e2c .5.3..Date:.Sun,
0x0080: 2030 3820 4465 6320 3230 3139 2031 313a .08.Dec.2019.11:
0x0090: 3331 3a32 3520 474d 540d 0a43 6f6e 6e65 31:25.GMT..Conne
0x00a0: 6374 696f 6e3a 2063 6c6f 7365 0d0a 436f ction:.close..Co
0x00b0: 6e74 656e 742d 5479 7065 3a20 7465 7874 ntent-Type:.text
0x00c0: 2f68 746d 6c3b 6368 6172 7365 743d 7574 /html;charset=ut
0x00d0: 662d 380d 0a43 6f6e 7465 6e74 2d4c 656e f-8..Content-Len
0x00e0: 6774 683a 2034 3639 0d0a 0d0a gth:.469....
12:31:25.864043 IP 172.16.20.130.13020 > 94.36.158.56.60270: Flags [FP.], seq 185:654, ack 85, win 114, options [nop,nop,TS val 3291355480 ecr 291161609], length 469
0x0000: 4500 0209 1798 4000 4006 3b7c ac10 1482 E.....@.@.;|....
0x0010: 5f2e c61a 32dc eb6e bb93 0f79 1d80 4e7e _...2..n...y..N~
0x0020: 8019 0072 2111 0000 0101 080a c42e 1958 ...r!..........X
0x0030: 115a c609 3c21 444f 4354 5950 4520 4854 .Z..<!DOCTYPE.HT
0x0040: 4d4c 2050 5542 4c49 4320 222d 2f2f 5733 ML.PUBLIC."-//W3
0x0050: 432f 2f44 5444 2048 544d 4c20 342e 3031 C//DTD.HTML.4.01
0x0060: 2f2f 454e 220a 2020 2020 2020 2020 2268 //EN"........."h
0x0070: 7474 703a 2f2f 7777 772e 7733 2e6f 7267 ttp://www.w3.org
0x0080: 2f54 522f 6874 6d6c 342f 7374 7269 6374 /TR/html4/strict
0x0090: 2e64 7464 223e 0a3c 6874 6d6c 3e0a 2020 .dtd">.<html>...
0x00a0: 2020 3c68 6561 643e 0a20 2020 2020 2020 ..<head>........
0x00b0: 203c 6d65 7461 2068 7474 702d 6571 7569 .<meta.http-equi
0x00c0: 763d 2243 6f6e 7465 6e74 2d54 7970 6522 v="Content-Type"
0x00d0: 2063 6f6e 7465 6e74 3d22 7465 7874 2f68 .content="text/h
0x00e0: 746d 6c3b 6368 6172 7365 743d 7574 662d tml;charset=utf-
12:31:26.006798 IP 94.36.158.56.60270 > 172.16.20.130.13020: Flags [.], ack 185, win 221, options [nop,nop,TS val 291161733 ecr 3291355480], length 0
0x0000: 4500 0034 4553 4000 3906 1696 5f2e c61a E..4ES@.9..._...
0x0010: ac10 1482 eb6e 32dc 1d80 4e7e bb93 0f79 .....n2...N~...y
0x0020: 8010 00dd 8548 0000 0101 080a 115a c685 .....H.......Z..
0x0030: c42e 1958 ...X
12:31:26.009713 IP 94.36.158.56.60270 > 172.16.20.130.13020: Flags [F.], seq 85, ack 655, win 230, options [nop,nop,TS val 291161733 ecr 3291355480], length 0
0x0000: 4500 0034 4554 4000 3906 1695 5f2e c61a E..4ET@.9..._...
0x0010: ac10 1482 eb6e 32dc 1d80 4e7e bb93 114f .....n2...N~...O
0x0020: 8011 00e6 8368 0000 0101 080a 115a c685 .....h.......Z..
0x0030: c42e 1958 ...X
12:31:26.009788 IP 172.16.20.130.13020 > 94.36.158.56.60270: Flags [.], ack 86, win 114, options [nop,nop,TS val 3291355626 ecr 291161733], length 0
0x0000: 4500 0034 1799 4000 4006 3d50 ac10 1482 E..4..@.@.=P....
0x0010: 5f2e c61a 32dc eb6e bb93 114f 1d80 4e7f _...2..n...O..N.
0x0020: 8010 0072 834a 0000 0101 080a c42e 19ea ...r.J..........
0x0030: 115a c685 .Z..
^C
10 packets captured
10 packets received by filter
0 packets dropped by kernel