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pietrodito's questions

Martin Hope
pietrodito
Asked: 2022-07-09 06:23:53 +0800 CST
  • 6

Existe um site específico www.balaye.netque não consigo acessar da minha área de trabalho do arco quando o resto da internet funciona sem problemas.

Eu tentei usar duas redes WiFi diferentes sem sucesso. Além disso, posso acessar o URL de outros dispositivos com Windows ou Android.

Aqui está minha configuração, mas não tenho certeza do que preciso fornecer:

Arquivo:/etc/resolv.conf

# Generated by NetworkManager
nameserver 192.168.214.185

Ao usarnslookup www.balaye.net

Server:         192.168.214.185
Address:        192.168.214.185#53

Non-authoritative answer:
www.balaye.net  canonical name = https://pietrodito.github.io.
Name:   https://pietrodito.github.io
Address: 185.199.111.153
Name:   https://pietrodito.github.io
Address: 185.199.108.153
Name:   https://pietrodito.github.io
Address: 185.199.110.153
Name:   https://pietrodito.github.io
Address: 185.199.109.153
Name:   https://pietrodito.github.io
Address: 2606:50c0:8001::153
Name:   https://pietrodito.github.io
Address: 2606:50c0:8000::153
Name:   https://pietrodito.github.io
Address: 2606:50c0:8003::153
Name:   https://pietrodito.github.io
Address: 2606:50c0:8002::153

Ao usardig www.balaye.net

; <<>> DiG 9.18.4 <<>> www.balaye.net
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 29574
;; flags: qr rd ra ad; QUERY: 1, ANSWER: 5, AUTHORITY: 0, ADDITIONAL: 0

;; QUESTION SECTION:
;www.balaye.net.                        IN      A

;; ANSWER SECTION:
www.balaye.net.         159     IN      CNAME   https://pietrodito.github.io.
https://pietrodito.github.io. 159 IN    A       185.199.110.153
https://pietrodito.github.io. 159 IN    A       185.199.109.153
https://pietrodito.github.io. 159 IN    A       185.199.111.153
https://pietrodito.github.io. 159 IN    A       185.199.108.153

;; Query time: 10 msec
;; SERVER: 192.168.214.185#53(192.168.214.185) (UDP)
;; WHEN: Fri Jul 08 16:19:31 CEST 2022
;; MSG SIZE  rcvd: 138

Eu tentei também isso wget https://www.balaye.net:

--2022-07-08 19:19:53--  https://www.balaye.net/
Loaded CA certificate '/etc/ssl/certs/ca-certificates.crt'
Resolving www.balaye.net (www.balaye.net)... failed: Success.
wget: unable to resolve host address ‘www.balaye.net’

E ao tentar ping www.balaye.net:

ping: www.balaye.net: System error

E ao tentar ping www.google.com:

ING www.google.com (216.58.214.164) 56(84) bytes of data.
64 bytes from par10s42-in-f4.1e100.net (216.58.214.164): icmp_seq=1 ttl=115 time=53.7 ms
64 bytes from par10s42-in-f4.1e100.net (216.58.214.164): icmp_seq=2 ttl=115 time=47.6 ms
64 bytes from par10s42-in-f4.1e100.net (216.58.214.164): icmp_seq=3 ttl=115 time=58.4 ms
64 bytes from par10s42-in-f4.1e100.net (216.58.214.164): icmp_seq=4 ttl=115 time=60.6 ms
^C
--- www.google.com ping statistics ---
4 packets transmitted, 4 received, 0% packet loss, time 3005ms
rtt min/avg/max/mdev = 47.585/55.077/60.585/4.986 ms
domain-name-system
Martin Hope
pietrodito
Asked: 2019-08-14 07:11:32 +0800 CST
  • 5

O título é explícito.

Etapas reproduzíveis

* Inicie uma instância do Ubuntu na AWS com regra HTTP na porta 80

* Instalar sbcl

sudo apt install sbcl -y

* Instale a biblioteca usocket para root

Veja o próximo passo para entender porque estou fazendo isso como root

curl -O https://beta.quicklisp.org/quicklisp.lisp
sudo sbcl --load quicklisp.lisp

As próximas linhas precisam ser digitadas em sbcl REPL

(quicklisp-quickstart:install)
(ql:add-to-init-file)
(ql:quickload "usocket")

* Use o exemplo Land of Lisp ( http://landoflisp.com/ )

Em um arquivo chamadoserver.lisp

(require 'usocket)

(defun http-char (c1 c2 &optional (default #\Space))
  (let ((code (parse-integer
               (coerce (list c1 c2) 'string)
               :radix 16
               :junk-allowed t)))
    (if code
        (code-char code)
        default)))

(defun decode-param (s)
  (labels ((f (lst)
             (when lst
               (case (car lst)
                 (#\% (cons (http-char (cadr lst) (caddr lst))
                            (f (cdddr lst))))
                 (#\+ (cons #\space (f (cdr lst))))
                 (otherwise (cons (car lst) (f (cdr lst))))))))
    (coerce (f (coerce s 'list)) 'string)))

(defun parse-params (s)
  (let* ((i1 (position #\= s))
         (i2 (position #\& s)))
    (cond (i1 (cons (cons (intern (string-upcase (subseq s 0 i1)))
                          (decode-param (subseq s (1+ i1) i2)))
                    (and i2 (parse-params (subseq s (1+ i2))))))
          ((equal s "") nil)
          (t s))))

(defun parse-url (s)
  (let* ((url (subseq s
                      (+ 2 (position #\space s))
                      (position #\space s :from-end t)))
         (x (position #\? url)))
    (if x
        (cons (subseq url 0 x) (parse-params (subseq url (1+ x))))
        (cons url '()))))


(defun get-header (stream)
  (let* ((s (read-line stream))
         (h (let ((i (position #\: s)))
              (when i
                (cons (intern (string-upcase (subseq s 0 i)))
                      (subseq s (+ i 2)))))))
    (when h
      (cons h (get-header stream)))))

(defun get-content-params (stream header)
  (let ((length (cdr (assoc 'content-length header))))
    (when length
      (let ((content (make-string (parse-integer length))))
        (read-sequence content stream)
        (parse-params content)))))

(defun serve (request-handler)
  (let ((socket (usocket:socket-listen #(127 0 0 1) 80)))
    (unwind-protect
         (loop (with-open-stream (stream (usocket:socket-stream
                                          (usocket:socket-accept socket)))
                 (let* ((url    (parse-url (read-line stream)))
                        (path   (car url))
                        (header (get-header stream))
                        (params (append (cdr url)
                                        (get-content-params stream header)))
                        (*standard-output* stream))
                   (funcall request-handler path header params))))
      (usocket:socket-close socket))))

(defun hello-request-handler (path header params)
  (if (equal path "greeting")
      (let ((name (assoc 'name params)))
        (if (not name)
            (princ "<html><form>What is your name?<input name='name'/></form></html>")
            (format t "<html>Nice to meet you, ~a!</html>" (cdr name))))
      (princ "Sorry... I don't know that page")))

(serve #'hello-request-handler)

Então você inicia o servidor como root:

sudo sbcl --load "server.lisp"

Estou usando root porque não consigo me livrar da seguinte mensagem de erro com um usuário normal

The condition Socket error in "bind": 13 (Permission denied) occurred with errno :0.

Então tudo parece estar certo, mas não consigo acessar o servidor de um navegador padrão usando:

http://IPv4.Public.IP:80

* Diagnósticos complementares:

Grupo de segurança da AWS/regras de entrada

╔══════╦══════════╦════════════╦═══════════╗
║ Type ║ Protocol ║ Port Range ║  Source   ║
╠══════╬══════════╬════════════╬═══════════╣
║ HTTP ║ TCP      ║         80 ║ 0.0.0.0/0 ║
║ HTTP ║ TCP      ║         80 ║ ::/0      ║
║ SSH  ║ TCP      ║         22 ║ 0.0.0.0/0 ║
╚══════╩══════════╩════════════╩═══════════╝

iptables

sudo iptables -L -v

Chain INPUT (policy ACCEPT 346 packets, 23760 bytes)
 pkts bytes target     prot opt in     out     source               destination

Chain FORWARD (policy ACCEPT 0 packets, 0 bytes)
 pkts bytes target     prot opt in     out     source               destination

Chain OUTPUT (policy ACCEPT 244 packets, 32428 bytes)
 pkts bytes target     prot opt in     out     source               destination

sudo iptables -t nat -L -v

Chain PREROUTING (policy ACCEPT)
target     prot opt source               destination

Chain INPUT (policy ACCEPT)
target     prot opt source               destination

Chain OUTPUT (policy ACCEPT)
target     prot opt source               destination

Chain POSTROUTING (policy ACCEPT)
target     prot opt source               destination

enrolar no servidor

curl 127.0.0.1

Sorry... I don't know that page

como esperado !

ping de máquina distante

É necessário adicionar uma regra ICMP personalizada à política de grupo de segurança de entrada (agora sei que pingestá usando ICMP ...)

ping 35.180.138.87

64 bytes from 35.180.138.87: icmp_seq=1 ttl=49 time=173 ms
64 bytes from 35.180.138.87: icmp_seq=2 ttl=49 time=32.2 ms
^C
--- 35.180.138.87 ping statistics ---
2 packets transmitted, 2 received, 0% packet loss, time 1005ms
rtt min/avg/max/mdev = 32.248/102.884/173.520/70.636 ms

enrolar da máquina distante

curl 35.180.138.87

curl: (7) Failed to connect to 35.180.138.87 port 80: Connection refused

netstat

netstat -nlp

Proto Recv-Q Send-Q Local Address           Foreign Address         State      
tcp        0      0 127.0.0.1:80            0.0.0.0:*               LISTEN      -

Essa linha com a porta 80 só aparece quando meu servidor está rodando.

http amazon-web-services