SSH stopped working after updating UTM to 9.4

Question

Hello All, 
 After updating one of the UTMs to 9.4, I am not able to login using SSH. I tried the following: 
 
 Disable/Enable SSH 
 Rebooted UTM 
 Tried Putty and Dameware 
 Changed ssh port 
 Disabled FW/AV...etc 
 
 When connecting using putty I got the message "Network error:Software caused connection abort", using Dameware I got "couldn't negotiate encryption algorithm" 
 I am able to login as usual to all the non-updated UTMs. 
 Any idea? 
 Thanks

isoffice · Accepted Answer

Hi, 
 We also had this issue when we updated to Firmware Version 9.403-4. 
 Putty (Release 0.59) came back with the error "Network error: Software caused connection abort". 
 However Tera Term was able to connect without any issue. I also downloaded the latest version (Release 0.67) of Putty and that worked fine as well. 
 No clue as to why this happened, but an installation of the latest version of Putty should get you re-connected. 
 Hope this helps. 
 JP

BAlfson · Answer

JP has it exactly right. I posted about this two weeks ago. You will see lines like the following in the SSH Server log: 
 2016:06:04-11:57:58 sophos sshd[12426]: fatal: no matching mac found: client hmac-sha1,hmac-sha1-96,hmac-md5 server umac-64-etm@openssh.com,umac-128-etm@openssh.com,hmac-sha2-256-etm@openssh.com,hmac-sha2-512-etm@openssh.com,umac-64@openssh.com,umac-128@openssh.com,hmac-sha2-256,hmac-sha2-512 [preauth] 
 Cheers - Bob