Extend or inherit existing entries in .ssh/config











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I have the following entry in my .ssh/config file:



Host myhost
Hostname localhost
User me
ServerAliveInterval 30
ProxyCommand ssh -q external-relay /usr/bin/nc -w 90 localhost 9889


Very simple, it allows me to access myhost from outside its NATed network, by bouncing off external-relay.



Most of the times I only want to SSH to myhost, without creating any SSH tunnels, but some other times I want to create various tunnels, for different purposes.



Nowadays I simply manually append the -L tunnel entries when I ssh to myhost but it's becoming increasingly difficult to remember which sets of ports I need for which purpose.



I could just add those custom port forwarding commands as aliases, but what I'd really like is to have separate named entries in my .ssh/config file that basically create the connection to myhost and add the required tunnels, but I don't want to duplicate the whole myhost config everytime, because if/when I change the external-relay, I don't want to have to remember to change it in every entry that used it.



Is there a way to create an entry that inherits fom the myhost entry, and simply appends the required LocalForward directives for that particular tunnel case?










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    I have the following entry in my .ssh/config file:



    Host myhost
    Hostname localhost
    User me
    ServerAliveInterval 30
    ProxyCommand ssh -q external-relay /usr/bin/nc -w 90 localhost 9889


    Very simple, it allows me to access myhost from outside its NATed network, by bouncing off external-relay.



    Most of the times I only want to SSH to myhost, without creating any SSH tunnels, but some other times I want to create various tunnels, for different purposes.



    Nowadays I simply manually append the -L tunnel entries when I ssh to myhost but it's becoming increasingly difficult to remember which sets of ports I need for which purpose.



    I could just add those custom port forwarding commands as aliases, but what I'd really like is to have separate named entries in my .ssh/config file that basically create the connection to myhost and add the required tunnels, but I don't want to duplicate the whole myhost config everytime, because if/when I change the external-relay, I don't want to have to remember to change it in every entry that used it.



    Is there a way to create an entry that inherits fom the myhost entry, and simply appends the required LocalForward directives for that particular tunnel case?










    share|improve this question
























      up vote
      0
      down vote

      favorite









      up vote
      0
      down vote

      favorite











      I have the following entry in my .ssh/config file:



      Host myhost
      Hostname localhost
      User me
      ServerAliveInterval 30
      ProxyCommand ssh -q external-relay /usr/bin/nc -w 90 localhost 9889


      Very simple, it allows me to access myhost from outside its NATed network, by bouncing off external-relay.



      Most of the times I only want to SSH to myhost, without creating any SSH tunnels, but some other times I want to create various tunnels, for different purposes.



      Nowadays I simply manually append the -L tunnel entries when I ssh to myhost but it's becoming increasingly difficult to remember which sets of ports I need for which purpose.



      I could just add those custom port forwarding commands as aliases, but what I'd really like is to have separate named entries in my .ssh/config file that basically create the connection to myhost and add the required tunnels, but I don't want to duplicate the whole myhost config everytime, because if/when I change the external-relay, I don't want to have to remember to change it in every entry that used it.



      Is there a way to create an entry that inherits fom the myhost entry, and simply appends the required LocalForward directives for that particular tunnel case?










      share|improve this question













      I have the following entry in my .ssh/config file:



      Host myhost
      Hostname localhost
      User me
      ServerAliveInterval 30
      ProxyCommand ssh -q external-relay /usr/bin/nc -w 90 localhost 9889


      Very simple, it allows me to access myhost from outside its NATed network, by bouncing off external-relay.



      Most of the times I only want to SSH to myhost, without creating any SSH tunnels, but some other times I want to create various tunnels, for different purposes.



      Nowadays I simply manually append the -L tunnel entries when I ssh to myhost but it's becoming increasingly difficult to remember which sets of ports I need for which purpose.



      I could just add those custom port forwarding commands as aliases, but what I'd really like is to have separate named entries in my .ssh/config file that basically create the connection to myhost and add the required tunnels, but I don't want to duplicate the whole myhost config everytime, because if/when I change the external-relay, I don't want to have to remember to change it in every entry that used it.



      Is there a way to create an entry that inherits fom the myhost entry, and simply appends the required LocalForward directives for that particular tunnel case?







      ssh ssh-tunnel






      share|improve this question













      share|improve this question











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      share|improve this question










      asked Nov 23 at 17:04









      ktorn

      1032




      1032






















          1 Answer
          1






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          up vote
          1
          down vote



          accepted










          You should be able to do:



          Host myhost-*
          Hostname localhost
          User me
          ServerAliveInterval 30
          ProxyCommand ssh -q external-relay /usr/bin/nc -w 90 localhost 9889


          followed by:



          Host myhost-1
          LocalForward ...

          Host myhost-2
          RemoteForward ...
          :


          myhots-1 and myhost-2 will derive settings from myhost-* (but CANNOT override them).



          You definitely should have a look at the beginning of DESCRIPTION section (to see how options are applied to connection) and PATTERNS section of ssh_config man page.






          share|improve this answer





















          • This works. I actually knew about the patterns and already used a wildcard for global options, but hadn't occurred to me to re-use the same host prefix to achieve what I wanted here. Thanks!
            – ktorn
            Nov 24 at 14:48











          Your Answer








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          1 Answer
          1






          active

          oldest

          votes








          1 Answer
          1






          active

          oldest

          votes









          active

          oldest

          votes






          active

          oldest

          votes








          up vote
          1
          down vote



          accepted










          You should be able to do:



          Host myhost-*
          Hostname localhost
          User me
          ServerAliveInterval 30
          ProxyCommand ssh -q external-relay /usr/bin/nc -w 90 localhost 9889


          followed by:



          Host myhost-1
          LocalForward ...

          Host myhost-2
          RemoteForward ...
          :


          myhots-1 and myhost-2 will derive settings from myhost-* (but CANNOT override them).



          You definitely should have a look at the beginning of DESCRIPTION section (to see how options are applied to connection) and PATTERNS section of ssh_config man page.






          share|improve this answer





















          • This works. I actually knew about the patterns and already used a wildcard for global options, but hadn't occurred to me to re-use the same host prefix to achieve what I wanted here. Thanks!
            – ktorn
            Nov 24 at 14:48















          up vote
          1
          down vote



          accepted










          You should be able to do:



          Host myhost-*
          Hostname localhost
          User me
          ServerAliveInterval 30
          ProxyCommand ssh -q external-relay /usr/bin/nc -w 90 localhost 9889


          followed by:



          Host myhost-1
          LocalForward ...

          Host myhost-2
          RemoteForward ...
          :


          myhots-1 and myhost-2 will derive settings from myhost-* (but CANNOT override them).



          You definitely should have a look at the beginning of DESCRIPTION section (to see how options are applied to connection) and PATTERNS section of ssh_config man page.






          share|improve this answer





















          • This works. I actually knew about the patterns and already used a wildcard for global options, but hadn't occurred to me to re-use the same host prefix to achieve what I wanted here. Thanks!
            – ktorn
            Nov 24 at 14:48













          up vote
          1
          down vote



          accepted







          up vote
          1
          down vote



          accepted






          You should be able to do:



          Host myhost-*
          Hostname localhost
          User me
          ServerAliveInterval 30
          ProxyCommand ssh -q external-relay /usr/bin/nc -w 90 localhost 9889


          followed by:



          Host myhost-1
          LocalForward ...

          Host myhost-2
          RemoteForward ...
          :


          myhots-1 and myhost-2 will derive settings from myhost-* (but CANNOT override them).



          You definitely should have a look at the beginning of DESCRIPTION section (to see how options are applied to connection) and PATTERNS section of ssh_config man page.






          share|improve this answer












          You should be able to do:



          Host myhost-*
          Hostname localhost
          User me
          ServerAliveInterval 30
          ProxyCommand ssh -q external-relay /usr/bin/nc -w 90 localhost 9889


          followed by:



          Host myhost-1
          LocalForward ...

          Host myhost-2
          RemoteForward ...
          :


          myhots-1 and myhost-2 will derive settings from myhost-* (but CANNOT override them).



          You definitely should have a look at the beginning of DESCRIPTION section (to see how options are applied to connection) and PATTERNS section of ssh_config man page.







          share|improve this answer












          share|improve this answer



          share|improve this answer










          answered Nov 23 at 17:57









          Tomek

          1564




          1564












          • This works. I actually knew about the patterns and already used a wildcard for global options, but hadn't occurred to me to re-use the same host prefix to achieve what I wanted here. Thanks!
            – ktorn
            Nov 24 at 14:48


















          • This works. I actually knew about the patterns and already used a wildcard for global options, but hadn't occurred to me to re-use the same host prefix to achieve what I wanted here. Thanks!
            – ktorn
            Nov 24 at 14:48
















          This works. I actually knew about the patterns and already used a wildcard for global options, but hadn't occurred to me to re-use the same host prefix to achieve what I wanted here. Thanks!
          – ktorn
          Nov 24 at 14:48




          This works. I actually knew about the patterns and already used a wildcard for global options, but hadn't occurred to me to re-use the same host prefix to achieve what I wanted here. Thanks!
          – ktorn
          Nov 24 at 14:48


















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