我自己之前一直都係做Support role,所以我可以同你講patch+backup+換硬野喺in-house一定唔係support做,一定係infra/sa regular要做嘅野
Firewall 係咪一定要學,我會覺得唔係,但你唔可以無concept ,因為大部分in-house firewall都係network/security team睇
你問我係SI跟開咩多,因為我係SI係做Support role,所以基本上d客嘅Endpoint,System有咩頭暈身慶都關我事

但如果Ching你係想入返in-house做infra/sa,我會覺得有d base野你一定要知,唔洗話精先但一定要了解。
咁話明SA,咁你可以簡單咁去區分為System + Admin野
System 嘅就
VMware:
VC係乜,ESXI係乜,ESXI同VC嘅關係,Vmotion
Storage - VSAN係乜 簡單嘅setting
VM - 點起VM ,form HA,點take同倒snapshot
Hyper-V :
同VC要知嘅野差不多,都係機點起,點做failover etc
Linux :
一d基本command要識
Windows:
成日要用嘅Command
唔同嘅server要識(AD,LDAP等等)
慢慢學下powershell script <- 呢個我都學緊

落patch/task scheduler,GPO,SCCM
其他野:
換硬野,work with vendor,做upgrade,呢d就唔講啦多了
Admin嘅野:
整user guide
Grant Access
做proposal
太多太多了,唔舉例了
Ching我都係做左好幾年野,唔敢話教你d乜,大家都係交流下,其他Ching睇下有冇咩可以補充

共勉之