{"id":4980,"date":"2026-03-04T16:29:22","date_gmt":"2026-03-04T16:29:22","guid":{"rendered":"https:\/\/geekmungus.co.uk\/?p=4980"},"modified":"2026-03-04T16:30:20","modified_gmt":"2026-03-04T16:30:20","slug":"mremoteng-couldnt-agree-a-host-key-algorithm-available-rsa-sha2-256","status":"publish","type":"post","link":"https:\/\/geekmungus.co.uk\/?p=4980","title":{"rendered":"mRemoteNG – Couldn’t agree a host key algorithm (available rsa-sha2-256)"},"content":{"rendered":"\n

I was having the issue in mRemoteNG where some hosts were showing the error: “Couldn’t agree a host key algorithm (available rsa-sha2-256)” when attempting to SSH to them.<\/p>\n\n\n\n

\"\"<\/figure>\n\n\n\n

And even when ensuring all the ciphers are enabled with the Default Settings (session) -> Connection -> SSH -> Cipher, the issue was still observed.<\/p>\n\n\n\n

\"\"<\/figure>\n\n\n\n

Turns out the mRemoteNG uses its own version of Putty, called PuttyNG.exe in my case I was using an older version, hence the issue appearing, no amount of upgrading my normal Putty or updating the configurations would help.<\/p>\n\n\n\n

Resolution<\/h2>\n\n\n\n
    \n
  1. Download the new version of PuTTYNG (version 0.83 at the time of writing) from https:\/\/github.com\/mRemoteNG\/PuTTYNG\/releases<\/a><\/li>\n\n\n\n
  2. Take a backup of the existing version, e.g. rename to PuTTYNG-old.exe for example.<\/li>\n\n\n\n
  3. Place PuTTYNG.exe into mRemoteNG directory overwriting the existing version my directory was: c:\\Program Files (x86)\\mRemoteNG<\/strong> yours may differ. <\/li>\n<\/ol>\n\n\n\n
    \"\"<\/figure>\n\n\n\n

    You should now be able to log into these hosts via SSH without an issue.<\/p>\n","protected":false},"excerpt":{"rendered":"

    I was having the issue in mRemoteNG where some hosts were showing the error: “Couldn’t agree a host key algorithm (available rsa-sha2-256)” when attempting to SSH to them. And even when ensuring all the ciphers are enabled with the Default Settings (session) -> Connection -> SSH -> Cipher, the issue was still observed. Turns out … Read more<\/a><\/p>\n","protected":false},"author":4,"featured_media":3651,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[41,17],"tags":[],"class_list":["post-4980","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-extreme-networks","category-networking"],"_links":{"self":[{"href":"https:\/\/geekmungus.co.uk\/index.php?rest_route=\/wp\/v2\/posts\/4980","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/geekmungus.co.uk\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/geekmungus.co.uk\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/geekmungus.co.uk\/index.php?rest_route=\/wp\/v2\/users\/4"}],"replies":[{"embeddable":true,"href":"https:\/\/geekmungus.co.uk\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=4980"}],"version-history":[{"count":2,"href":"https:\/\/geekmungus.co.uk\/index.php?rest_route=\/wp\/v2\/posts\/4980\/revisions"}],"predecessor-version":[{"id":4985,"href":"https:\/\/geekmungus.co.uk\/index.php?rest_route=\/wp\/v2\/posts\/4980\/revisions\/4985"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/geekmungus.co.uk\/index.php?rest_route=\/wp\/v2\/media\/3651"}],"wp:attachment":[{"href":"https:\/\/geekmungus.co.uk\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=4980"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/geekmungus.co.uk\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=4980"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/geekmungus.co.uk\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=4980"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}