what is the required ports to be opened on the firewall?





.everyoneloves__top-leaderboard:empty,.everyoneloves__mid-leaderboard:empty,.everyoneloves__bot-mid-leaderboard:empty{ margin-bottom:0;
}







4















Currently I'll be installing one AIX server behind a firewall, I just asked to open port 443 to use the SSH protocol to access this UNIX server.



I already changed the default ssh port to be 443 instead of 22 to log in and manage the server.



My question: is this enough to access and manage this server which is behind the firewall or is there any additional ports that should be included in the firewall rules?










share|improve this question




















  • 4





    Using 443 seems a bad move as that port will get barrages of dud requests because it's the standard https port. Probably not a big deal, but if the duds are going to be rejected anyway, you might as well reject them more efficiently by leaving 443 closed too and choosing something more arbitrary.

    – goldilocks
    Jul 19 '13 at 0:26




















4















Currently I'll be installing one AIX server behind a firewall, I just asked to open port 443 to use the SSH protocol to access this UNIX server.



I already changed the default ssh port to be 443 instead of 22 to log in and manage the server.



My question: is this enough to access and manage this server which is behind the firewall or is there any additional ports that should be included in the firewall rules?










share|improve this question




















  • 4





    Using 443 seems a bad move as that port will get barrages of dud requests because it's the standard https port. Probably not a big deal, but if the duds are going to be rejected anyway, you might as well reject them more efficiently by leaving 443 closed too and choosing something more arbitrary.

    – goldilocks
    Jul 19 '13 at 0:26
















4












4








4


1






Currently I'll be installing one AIX server behind a firewall, I just asked to open port 443 to use the SSH protocol to access this UNIX server.



I already changed the default ssh port to be 443 instead of 22 to log in and manage the server.



My question: is this enough to access and manage this server which is behind the firewall or is there any additional ports that should be included in the firewall rules?










share|improve this question
















Currently I'll be installing one AIX server behind a firewall, I just asked to open port 443 to use the SSH protocol to access this UNIX server.



I already changed the default ssh port to be 443 instead of 22 to log in and manage the server.



My question: is this enough to access and manage this server which is behind the firewall or is there any additional ports that should be included in the firewall rules?







ssh firewall aix






share|improve this question















share|improve this question













share|improve this question




share|improve this question








edited Jul 18 '13 at 23:58









Gilles

546k12911101624




546k12911101624










asked Jul 18 '13 at 22:50









Maged RamezMaged Ramez

21112




21112








  • 4





    Using 443 seems a bad move as that port will get barrages of dud requests because it's the standard https port. Probably not a big deal, but if the duds are going to be rejected anyway, you might as well reject them more efficiently by leaving 443 closed too and choosing something more arbitrary.

    – goldilocks
    Jul 19 '13 at 0:26
















  • 4





    Using 443 seems a bad move as that port will get barrages of dud requests because it's the standard https port. Probably not a big deal, but if the duds are going to be rejected anyway, you might as well reject them more efficiently by leaving 443 closed too and choosing something more arbitrary.

    – goldilocks
    Jul 19 '13 at 0:26










4




4





Using 443 seems a bad move as that port will get barrages of dud requests because it's the standard https port. Probably not a big deal, but if the duds are going to be rejected anyway, you might as well reject them more efficiently by leaving 443 closed too and choosing something more arbitrary.

– goldilocks
Jul 19 '13 at 0:26







Using 443 seems a bad move as that port will get barrages of dud requests because it's the standard https port. Probably not a big deal, but if the duds are going to be rejected anyway, you might as well reject them more efficiently by leaving 443 closed too and choosing something more arbitrary.

– goldilocks
Jul 19 '13 at 0:26












3 Answers
3






active

oldest

votes


















5














This is security by obscurity, and you have chosen a port that in my experience is more often scanned. Just leave ssh on port 22 and get that opened. If you do plan to use security by obscurity, it is best not to pick a well known port. Scanning rates on them tends to be higher than other ports.



An alternative approach is to ssh into an already accessible system and connect from there. ssh can be programmed to automatically forward you to another system.



The only ports that need to be open to any network are those that are used. The list of outbound ports is usually different than inbound. You may want to retrieve patches from your vendor (often on port 80), while not allowing incoming HTTP requests.



Email should generally go to a relay server which will route it appropriately.






share|improve this answer



















  • 1





    Port 22 is often scanned for the same reason, so recommending someone "leave it on 22" instead of using 443 is sort of meaningless -- the point about using a genuinely obscure port is better.

    – goldilocks
    Jul 19 '13 at 0:22








  • 2





    @goldilocks When I was monitoring scanning on ports 22 and 443, it was 443 that was scanned more frequently. That is one of the reasons I said to leave in on 22. There are a number of ways to secure ssh, and I apply a stack of them. The preferable option, is to use an already open server as a gateway, but failing that security by obscurity generally isn't secure.

    – BillThor
    Jul 19 '13 at 0:27






  • 1





    If ssh isn't secure to start with, there's probably not much you can do about it. WRT to 443 vs. 22, I agree 443 will get scanned more often, but my point was if you don't want or need to use the standard port, then don't -- "You might as well" just seems wishy-washy logic.

    – goldilocks
    Jul 19 '13 at 0:36











  • @goldilocks It has been my experience that using an obscure port is seen as having secured the service. As a result not much thought goes into properly securing it. It is better to secure the service well, in which case an obscure port invites forgetting which obscure port it is on, or forgetting that it is running. As soon as your custom entry for secure-ssh gets dropped form /etc/services tools like netstat won't make open connections obvious.

    – BillThor
    Jul 19 '13 at 0:56











  • Security by obscurity is a damn stupid policy anyway because it tends to lull you into a false sense of security "hurr hurr, they'll never guess this is here". Put ssh back on the port it belongs and set up fail2ban to deal with scanners and brute force attacks.

    – Shadur
    Jul 19 '13 at 6:27



















4














If you're only interested in remoting into this server using SSH on port 443, then what you've done is sufficient.






share|improve this answer































    2














    to see what ports are being listened to (blocked by a firewall or otherwise)



    as root, run



    netstat -lp


    This will list all open ports, and what applications are listening. then you can open the ports you need in your firewall.






    share|improve this answer


























      Your Answer








      StackExchange.ready(function() {
      var channelOptions = {
      tags: "".split(" "),
      id: "106"
      };
      initTagRenderer("".split(" "), "".split(" "), channelOptions);

      StackExchange.using("externalEditor", function() {
      // Have to fire editor after snippets, if snippets enabled
      if (StackExchange.settings.snippets.snippetsEnabled) {
      StackExchange.using("snippets", function() {
      createEditor();
      });
      }
      else {
      createEditor();
      }
      });

      function createEditor() {
      StackExchange.prepareEditor({
      heartbeatType: 'answer',
      autoActivateHeartbeat: false,
      convertImagesToLinks: false,
      noModals: true,
      showLowRepImageUploadWarning: true,
      reputationToPostImages: null,
      bindNavPrevention: true,
      postfix: "",
      imageUploader: {
      brandingHtml: "Powered by u003ca class="icon-imgur-white" href="https://imgur.com/"u003eu003c/au003e",
      contentPolicyHtml: "User contributions licensed under u003ca href="https://creativecommons.org/licenses/by-sa/3.0/"u003ecc by-sa 3.0 with attribution requiredu003c/au003e u003ca href="https://stackoverflow.com/legal/content-policy"u003e(content policy)u003c/au003e",
      allowUrls: true
      },
      onDemand: true,
      discardSelector: ".discard-answer"
      ,immediatelyShowMarkdownHelp:true
      });


      }
      });














      draft saved

      draft discarded


















      StackExchange.ready(
      function () {
      StackExchange.openid.initPostLogin('.new-post-login', 'https%3a%2f%2funix.stackexchange.com%2fquestions%2f83575%2fwhat-is-the-required-ports-to-be-opened-on-the-firewall%23new-answer', 'question_page');
      }
      );

      Post as a guest















      Required, but never shown

























      3 Answers
      3






      active

      oldest

      votes








      3 Answers
      3






      active

      oldest

      votes









      active

      oldest

      votes






      active

      oldest

      votes









      5














      This is security by obscurity, and you have chosen a port that in my experience is more often scanned. Just leave ssh on port 22 and get that opened. If you do plan to use security by obscurity, it is best not to pick a well known port. Scanning rates on them tends to be higher than other ports.



      An alternative approach is to ssh into an already accessible system and connect from there. ssh can be programmed to automatically forward you to another system.



      The only ports that need to be open to any network are those that are used. The list of outbound ports is usually different than inbound. You may want to retrieve patches from your vendor (often on port 80), while not allowing incoming HTTP requests.



      Email should generally go to a relay server which will route it appropriately.






      share|improve this answer



















      • 1





        Port 22 is often scanned for the same reason, so recommending someone "leave it on 22" instead of using 443 is sort of meaningless -- the point about using a genuinely obscure port is better.

        – goldilocks
        Jul 19 '13 at 0:22








      • 2





        @goldilocks When I was monitoring scanning on ports 22 and 443, it was 443 that was scanned more frequently. That is one of the reasons I said to leave in on 22. There are a number of ways to secure ssh, and I apply a stack of them. The preferable option, is to use an already open server as a gateway, but failing that security by obscurity generally isn't secure.

        – BillThor
        Jul 19 '13 at 0:27






      • 1





        If ssh isn't secure to start with, there's probably not much you can do about it. WRT to 443 vs. 22, I agree 443 will get scanned more often, but my point was if you don't want or need to use the standard port, then don't -- "You might as well" just seems wishy-washy logic.

        – goldilocks
        Jul 19 '13 at 0:36











      • @goldilocks It has been my experience that using an obscure port is seen as having secured the service. As a result not much thought goes into properly securing it. It is better to secure the service well, in which case an obscure port invites forgetting which obscure port it is on, or forgetting that it is running. As soon as your custom entry for secure-ssh gets dropped form /etc/services tools like netstat won't make open connections obvious.

        – BillThor
        Jul 19 '13 at 0:56











      • Security by obscurity is a damn stupid policy anyway because it tends to lull you into a false sense of security "hurr hurr, they'll never guess this is here". Put ssh back on the port it belongs and set up fail2ban to deal with scanners and brute force attacks.

        – Shadur
        Jul 19 '13 at 6:27
















      5














      This is security by obscurity, and you have chosen a port that in my experience is more often scanned. Just leave ssh on port 22 and get that opened. If you do plan to use security by obscurity, it is best not to pick a well known port. Scanning rates on them tends to be higher than other ports.



      An alternative approach is to ssh into an already accessible system and connect from there. ssh can be programmed to automatically forward you to another system.



      The only ports that need to be open to any network are those that are used. The list of outbound ports is usually different than inbound. You may want to retrieve patches from your vendor (often on port 80), while not allowing incoming HTTP requests.



      Email should generally go to a relay server which will route it appropriately.






      share|improve this answer



















      • 1





        Port 22 is often scanned for the same reason, so recommending someone "leave it on 22" instead of using 443 is sort of meaningless -- the point about using a genuinely obscure port is better.

        – goldilocks
        Jul 19 '13 at 0:22








      • 2





        @goldilocks When I was monitoring scanning on ports 22 and 443, it was 443 that was scanned more frequently. That is one of the reasons I said to leave in on 22. There are a number of ways to secure ssh, and I apply a stack of them. The preferable option, is to use an already open server as a gateway, but failing that security by obscurity generally isn't secure.

        – BillThor
        Jul 19 '13 at 0:27






      • 1





        If ssh isn't secure to start with, there's probably not much you can do about it. WRT to 443 vs. 22, I agree 443 will get scanned more often, but my point was if you don't want or need to use the standard port, then don't -- "You might as well" just seems wishy-washy logic.

        – goldilocks
        Jul 19 '13 at 0:36











      • @goldilocks It has been my experience that using an obscure port is seen as having secured the service. As a result not much thought goes into properly securing it. It is better to secure the service well, in which case an obscure port invites forgetting which obscure port it is on, or forgetting that it is running. As soon as your custom entry for secure-ssh gets dropped form /etc/services tools like netstat won't make open connections obvious.

        – BillThor
        Jul 19 '13 at 0:56











      • Security by obscurity is a damn stupid policy anyway because it tends to lull you into a false sense of security "hurr hurr, they'll never guess this is here". Put ssh back on the port it belongs and set up fail2ban to deal with scanners and brute force attacks.

        – Shadur
        Jul 19 '13 at 6:27














      5












      5








      5







      This is security by obscurity, and you have chosen a port that in my experience is more often scanned. Just leave ssh on port 22 and get that opened. If you do plan to use security by obscurity, it is best not to pick a well known port. Scanning rates on them tends to be higher than other ports.



      An alternative approach is to ssh into an already accessible system and connect from there. ssh can be programmed to automatically forward you to another system.



      The only ports that need to be open to any network are those that are used. The list of outbound ports is usually different than inbound. You may want to retrieve patches from your vendor (often on port 80), while not allowing incoming HTTP requests.



      Email should generally go to a relay server which will route it appropriately.






      share|improve this answer













      This is security by obscurity, and you have chosen a port that in my experience is more often scanned. Just leave ssh on port 22 and get that opened. If you do plan to use security by obscurity, it is best not to pick a well known port. Scanning rates on them tends to be higher than other ports.



      An alternative approach is to ssh into an already accessible system and connect from there. ssh can be programmed to automatically forward you to another system.



      The only ports that need to be open to any network are those that are used. The list of outbound ports is usually different than inbound. You may want to retrieve patches from your vendor (often on port 80), while not allowing incoming HTTP requests.



      Email should generally go to a relay server which will route it appropriately.







      share|improve this answer












      share|improve this answer



      share|improve this answer










      answered Jul 19 '13 at 0:07









      BillThorBillThor

      7,7531426




      7,7531426








      • 1





        Port 22 is often scanned for the same reason, so recommending someone "leave it on 22" instead of using 443 is sort of meaningless -- the point about using a genuinely obscure port is better.

        – goldilocks
        Jul 19 '13 at 0:22








      • 2





        @goldilocks When I was monitoring scanning on ports 22 and 443, it was 443 that was scanned more frequently. That is one of the reasons I said to leave in on 22. There are a number of ways to secure ssh, and I apply a stack of them. The preferable option, is to use an already open server as a gateway, but failing that security by obscurity generally isn't secure.

        – BillThor
        Jul 19 '13 at 0:27






      • 1





        If ssh isn't secure to start with, there's probably not much you can do about it. WRT to 443 vs. 22, I agree 443 will get scanned more often, but my point was if you don't want or need to use the standard port, then don't -- "You might as well" just seems wishy-washy logic.

        – goldilocks
        Jul 19 '13 at 0:36











      • @goldilocks It has been my experience that using an obscure port is seen as having secured the service. As a result not much thought goes into properly securing it. It is better to secure the service well, in which case an obscure port invites forgetting which obscure port it is on, or forgetting that it is running. As soon as your custom entry for secure-ssh gets dropped form /etc/services tools like netstat won't make open connections obvious.

        – BillThor
        Jul 19 '13 at 0:56











      • Security by obscurity is a damn stupid policy anyway because it tends to lull you into a false sense of security "hurr hurr, they'll never guess this is here". Put ssh back on the port it belongs and set up fail2ban to deal with scanners and brute force attacks.

        – Shadur
        Jul 19 '13 at 6:27














      • 1





        Port 22 is often scanned for the same reason, so recommending someone "leave it on 22" instead of using 443 is sort of meaningless -- the point about using a genuinely obscure port is better.

        – goldilocks
        Jul 19 '13 at 0:22








      • 2





        @goldilocks When I was monitoring scanning on ports 22 and 443, it was 443 that was scanned more frequently. That is one of the reasons I said to leave in on 22. There are a number of ways to secure ssh, and I apply a stack of them. The preferable option, is to use an already open server as a gateway, but failing that security by obscurity generally isn't secure.

        – BillThor
        Jul 19 '13 at 0:27






      • 1





        If ssh isn't secure to start with, there's probably not much you can do about it. WRT to 443 vs. 22, I agree 443 will get scanned more often, but my point was if you don't want or need to use the standard port, then don't -- "You might as well" just seems wishy-washy logic.

        – goldilocks
        Jul 19 '13 at 0:36











      • @goldilocks It has been my experience that using an obscure port is seen as having secured the service. As a result not much thought goes into properly securing it. It is better to secure the service well, in which case an obscure port invites forgetting which obscure port it is on, or forgetting that it is running. As soon as your custom entry for secure-ssh gets dropped form /etc/services tools like netstat won't make open connections obvious.

        – BillThor
        Jul 19 '13 at 0:56











      • Security by obscurity is a damn stupid policy anyway because it tends to lull you into a false sense of security "hurr hurr, they'll never guess this is here". Put ssh back on the port it belongs and set up fail2ban to deal with scanners and brute force attacks.

        – Shadur
        Jul 19 '13 at 6:27








      1




      1





      Port 22 is often scanned for the same reason, so recommending someone "leave it on 22" instead of using 443 is sort of meaningless -- the point about using a genuinely obscure port is better.

      – goldilocks
      Jul 19 '13 at 0:22







      Port 22 is often scanned for the same reason, so recommending someone "leave it on 22" instead of using 443 is sort of meaningless -- the point about using a genuinely obscure port is better.

      – goldilocks
      Jul 19 '13 at 0:22






      2




      2





      @goldilocks When I was monitoring scanning on ports 22 and 443, it was 443 that was scanned more frequently. That is one of the reasons I said to leave in on 22. There are a number of ways to secure ssh, and I apply a stack of them. The preferable option, is to use an already open server as a gateway, but failing that security by obscurity generally isn't secure.

      – BillThor
      Jul 19 '13 at 0:27





      @goldilocks When I was monitoring scanning on ports 22 and 443, it was 443 that was scanned more frequently. That is one of the reasons I said to leave in on 22. There are a number of ways to secure ssh, and I apply a stack of them. The preferable option, is to use an already open server as a gateway, but failing that security by obscurity generally isn't secure.

      – BillThor
      Jul 19 '13 at 0:27




      1




      1





      If ssh isn't secure to start with, there's probably not much you can do about it. WRT to 443 vs. 22, I agree 443 will get scanned more often, but my point was if you don't want or need to use the standard port, then don't -- "You might as well" just seems wishy-washy logic.

      – goldilocks
      Jul 19 '13 at 0:36





      If ssh isn't secure to start with, there's probably not much you can do about it. WRT to 443 vs. 22, I agree 443 will get scanned more often, but my point was if you don't want or need to use the standard port, then don't -- "You might as well" just seems wishy-washy logic.

      – goldilocks
      Jul 19 '13 at 0:36













      @goldilocks It has been my experience that using an obscure port is seen as having secured the service. As a result not much thought goes into properly securing it. It is better to secure the service well, in which case an obscure port invites forgetting which obscure port it is on, or forgetting that it is running. As soon as your custom entry for secure-ssh gets dropped form /etc/services tools like netstat won't make open connections obvious.

      – BillThor
      Jul 19 '13 at 0:56





      @goldilocks It has been my experience that using an obscure port is seen as having secured the service. As a result not much thought goes into properly securing it. It is better to secure the service well, in which case an obscure port invites forgetting which obscure port it is on, or forgetting that it is running. As soon as your custom entry for secure-ssh gets dropped form /etc/services tools like netstat won't make open connections obvious.

      – BillThor
      Jul 19 '13 at 0:56













      Security by obscurity is a damn stupid policy anyway because it tends to lull you into a false sense of security "hurr hurr, they'll never guess this is here". Put ssh back on the port it belongs and set up fail2ban to deal with scanners and brute force attacks.

      – Shadur
      Jul 19 '13 at 6:27





      Security by obscurity is a damn stupid policy anyway because it tends to lull you into a false sense of security "hurr hurr, they'll never guess this is here". Put ssh back on the port it belongs and set up fail2ban to deal with scanners and brute force attacks.

      – Shadur
      Jul 19 '13 at 6:27













      4














      If you're only interested in remoting into this server using SSH on port 443, then what you've done is sufficient.






      share|improve this answer




























        4














        If you're only interested in remoting into this server using SSH on port 443, then what you've done is sufficient.






        share|improve this answer


























          4












          4








          4







          If you're only interested in remoting into this server using SSH on port 443, then what you've done is sufficient.






          share|improve this answer













          If you're only interested in remoting into this server using SSH on port 443, then what you've done is sufficient.







          share|improve this answer












          share|improve this answer



          share|improve this answer










          answered Jul 18 '13 at 23:56









          slmslm

          255k71541687




          255k71541687























              2














              to see what ports are being listened to (blocked by a firewall or otherwise)



              as root, run



              netstat -lp


              This will list all open ports, and what applications are listening. then you can open the ports you need in your firewall.






              share|improve this answer






























                2














                to see what ports are being listened to (blocked by a firewall or otherwise)



                as root, run



                netstat -lp


                This will list all open ports, and what applications are listening. then you can open the ports you need in your firewall.






                share|improve this answer




























                  2












                  2








                  2







                  to see what ports are being listened to (blocked by a firewall or otherwise)



                  as root, run



                  netstat -lp


                  This will list all open ports, and what applications are listening. then you can open the ports you need in your firewall.






                  share|improve this answer















                  to see what ports are being listened to (blocked by a firewall or otherwise)



                  as root, run



                  netstat -lp


                  This will list all open ports, and what applications are listening. then you can open the ports you need in your firewall.







                  share|improve this answer














                  share|improve this answer



                  share|improve this answer








                  edited 1 hour ago









                  Rui F Ribeiro

                  41.9k1483142




                  41.9k1483142










                  answered Jul 18 '13 at 23:03









                  lordbraylordbray

                  513




                  513






























                      draft saved

                      draft discarded




















































                      Thanks for contributing an answer to Unix & Linux Stack Exchange!


                      • Please be sure to answer the question. Provide details and share your research!

                      But avoid



                      • Asking for help, clarification, or responding to other answers.

                      • Making statements based on opinion; back them up with references or personal experience.


                      To learn more, see our tips on writing great answers.




                      draft saved


                      draft discarded














                      StackExchange.ready(
                      function () {
                      StackExchange.openid.initPostLogin('.new-post-login', 'https%3a%2f%2funix.stackexchange.com%2fquestions%2f83575%2fwhat-is-the-required-ports-to-be-opened-on-the-firewall%23new-answer', 'question_page');
                      }
                      );

                      Post as a guest















                      Required, but never shown





















































                      Required, but never shown














                      Required, but never shown












                      Required, but never shown







                      Required, but never shown

































                      Required, but never shown














                      Required, but never shown












                      Required, but never shown







                      Required, but never shown







                      Popular posts from this blog

                      宮崎県

                      濃尾地震

                      シテ島