Packet flow between Client - Load balancer - Server












0















I am building my own load balancer in C++. But I lack some fundamental knowledge of how requests/responses flow in such routing configuration.
Suppose I have application at www.application.com and that DNS returns ip-address of Load balancer when requested. Client's ip is client_ip, balancer's one is balancer_ip and server's - server_ip. So here is sequence of packets generated in a network:



1) The first packet is generated by client requesting load balancer:



+-----------+-------------+---------+
| Source | Destination | Request |
+-----------+-------------+---------+
| client_ip | balancer_ip | /hello |
+-----------+-------------+---------+


2) The second one is generated by balancer making request to server and putting client_ip into X-Forwarded-For header:



+-------------+-------------+---------+-----------------+
| Source | Destination | Request | X-Forwarded-For |
+-------------+-------------+---------+-----------------+
| balancer_ip | server_ip | /hello | client_ip |
+-------------+-------------+---------+-----------------+


3) The server is receives request and makes response back to load balancer. X-Forwarded-For remains the same.



+-----------+-------------+------------------+-----------------+
| Source | Destination | Response | X-Forwarded-For |
+-----------+-------------+------------------+-----------------+
| server_ip | balancer_ip | response_message | client_ip |
+-----------+-------------+------------------+-----------------+


4) Balancer receives response from server and creates its own response back to client, by taking client's ip-address from X-Forwarded-For header and putting it into destination:



+-------------+-------------+------------------+
| Source | Destination | Response |
+-------------+-------------+------------------+
| balancer_ip | client_ip | response_message |
+-------------+-------------+------------------+


Suppose all communcation is performed in HTTP. Is this a correct way of performing redirects between client - load balancer - server? I have looked through standard request/response fields and X-Forwarded-For wasn't in the list of standard and non-standard responses. Also if this is the correct way, won't such popular frameworks such as Spring, Django, Node.js discard X-Forwarded-For header?










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    0















    I am building my own load balancer in C++. But I lack some fundamental knowledge of how requests/responses flow in such routing configuration.
    Suppose I have application at www.application.com and that DNS returns ip-address of Load balancer when requested. Client's ip is client_ip, balancer's one is balancer_ip and server's - server_ip. So here is sequence of packets generated in a network:



    1) The first packet is generated by client requesting load balancer:



    +-----------+-------------+---------+
    | Source | Destination | Request |
    +-----------+-------------+---------+
    | client_ip | balancer_ip | /hello |
    +-----------+-------------+---------+


    2) The second one is generated by balancer making request to server and putting client_ip into X-Forwarded-For header:



    +-------------+-------------+---------+-----------------+
    | Source | Destination | Request | X-Forwarded-For |
    +-------------+-------------+---------+-----------------+
    | balancer_ip | server_ip | /hello | client_ip |
    +-------------+-------------+---------+-----------------+


    3) The server is receives request and makes response back to load balancer. X-Forwarded-For remains the same.



    +-----------+-------------+------------------+-----------------+
    | Source | Destination | Response | X-Forwarded-For |
    +-----------+-------------+------------------+-----------------+
    | server_ip | balancer_ip | response_message | client_ip |
    +-----------+-------------+------------------+-----------------+


    4) Balancer receives response from server and creates its own response back to client, by taking client's ip-address from X-Forwarded-For header and putting it into destination:



    +-------------+-------------+------------------+
    | Source | Destination | Response |
    +-------------+-------------+------------------+
    | balancer_ip | client_ip | response_message |
    +-------------+-------------+------------------+


    Suppose all communcation is performed in HTTP. Is this a correct way of performing redirects between client - load balancer - server? I have looked through standard request/response fields and X-Forwarded-For wasn't in the list of standard and non-standard responses. Also if this is the correct way, won't such popular frameworks such as Spring, Django, Node.js discard X-Forwarded-For header?










    share|improve this question

























      0












      0








      0








      I am building my own load balancer in C++. But I lack some fundamental knowledge of how requests/responses flow in such routing configuration.
      Suppose I have application at www.application.com and that DNS returns ip-address of Load balancer when requested. Client's ip is client_ip, balancer's one is balancer_ip and server's - server_ip. So here is sequence of packets generated in a network:



      1) The first packet is generated by client requesting load balancer:



      +-----------+-------------+---------+
      | Source | Destination | Request |
      +-----------+-------------+---------+
      | client_ip | balancer_ip | /hello |
      +-----------+-------------+---------+


      2) The second one is generated by balancer making request to server and putting client_ip into X-Forwarded-For header:



      +-------------+-------------+---------+-----------------+
      | Source | Destination | Request | X-Forwarded-For |
      +-------------+-------------+---------+-----------------+
      | balancer_ip | server_ip | /hello | client_ip |
      +-------------+-------------+---------+-----------------+


      3) The server is receives request and makes response back to load balancer. X-Forwarded-For remains the same.



      +-----------+-------------+------------------+-----------------+
      | Source | Destination | Response | X-Forwarded-For |
      +-----------+-------------+------------------+-----------------+
      | server_ip | balancer_ip | response_message | client_ip |
      +-----------+-------------+------------------+-----------------+


      4) Balancer receives response from server and creates its own response back to client, by taking client's ip-address from X-Forwarded-For header and putting it into destination:



      +-------------+-------------+------------------+
      | Source | Destination | Response |
      +-------------+-------------+------------------+
      | balancer_ip | client_ip | response_message |
      +-------------+-------------+------------------+


      Suppose all communcation is performed in HTTP. Is this a correct way of performing redirects between client - load balancer - server? I have looked through standard request/response fields and X-Forwarded-For wasn't in the list of standard and non-standard responses. Also if this is the correct way, won't such popular frameworks such as Spring, Django, Node.js discard X-Forwarded-For header?










      share|improve this question














      I am building my own load balancer in C++. But I lack some fundamental knowledge of how requests/responses flow in such routing configuration.
      Suppose I have application at www.application.com and that DNS returns ip-address of Load balancer when requested. Client's ip is client_ip, balancer's one is balancer_ip and server's - server_ip. So here is sequence of packets generated in a network:



      1) The first packet is generated by client requesting load balancer:



      +-----------+-------------+---------+
      | Source | Destination | Request |
      +-----------+-------------+---------+
      | client_ip | balancer_ip | /hello |
      +-----------+-------------+---------+


      2) The second one is generated by balancer making request to server and putting client_ip into X-Forwarded-For header:



      +-------------+-------------+---------+-----------------+
      | Source | Destination | Request | X-Forwarded-For |
      +-------------+-------------+---------+-----------------+
      | balancer_ip | server_ip | /hello | client_ip |
      +-------------+-------------+---------+-----------------+


      3) The server is receives request and makes response back to load balancer. X-Forwarded-For remains the same.



      +-----------+-------------+------------------+-----------------+
      | Source | Destination | Response | X-Forwarded-For |
      +-----------+-------------+------------------+-----------------+
      | server_ip | balancer_ip | response_message | client_ip |
      +-----------+-------------+------------------+-----------------+


      4) Balancer receives response from server and creates its own response back to client, by taking client's ip-address from X-Forwarded-For header and putting it into destination:



      +-------------+-------------+------------------+
      | Source | Destination | Response |
      +-------------+-------------+------------------+
      | balancer_ip | client_ip | response_message |
      +-------------+-------------+------------------+


      Suppose all communcation is performed in HTTP. Is this a correct way of performing redirects between client - load balancer - server? I have looked through standard request/response fields and X-Forwarded-For wasn't in the list of standard and non-standard responses. Also if this is the correct way, won't such popular frameworks such as Spring, Django, Node.js discard X-Forwarded-For header?







      networking ip routing load-balancer






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      asked Jan 8 at 5:14









      TeamBeamTeamBeam

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