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I'm following the best security practices of SSH, via this link and the link states:

We should remove the unused keys and only generate a large RSA key and an Ed25519 key. Your init scripts may recreate the unused keys. If you don’t want that, remove any ssh-keygen commands from the init script.

However I can't find where this init script is located to remove the ssh-keygen command. I don't want my OS to recreate DSA and EDCSA keys at boot. I tried many places I thought it might be located, like /etc/rc.d and similar. My OS is OpenBSD 5.7

  • +1 for a good guide on SSH security practices. Want to know that too! – Freedo Jul 18 '15 at 19:20
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    Don't remove the keys or modify the init scripts. Instead disable the keys in sshd_config. – Rufo El Magufo Jul 18 '15 at 21:06
  • In a very secure server nobody would use this keys anyway...there's no reason to even let them exist – Freedo Jul 18 '15 at 23:55
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    Yes, but if you modify any init script you're going to mess up the updates. The sshd_config method is the cleaner one to disable obsolete algorithms. The output of sysmerge during the updates will be more simple. – Rufo El Magufo Jul 19 '15 at 1:23
  • By updates you mean like upgrading to 5.8 ? I would just download 5.8 iso and format it anyway. But if i knew that before i would just create a copy .backup but now is too late lol – Freedo Jul 19 '15 at 3:01
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On /etc/rc search for : ssh-keygen -A then delete this line. You should not recreate any keys at startup. I did this and i got no error warning on boot, but if anyone knows a "cleaner" way to do this, please answer! Also this work for OpenBSD only(i think) but should only be a matter of finding the right init script to remove this line on other unix variants.

Edit : If you want to preserve your init script if you ever need it to update your system do cd /etc then cp rc rc.backup . If you ever need your original script just remove rc and rename rc.backup to rc

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