UseDNSdefault

2017年8月3日—InRedHatEnterpriseLinux7.4,thedefaultvalueoftheUseDNSconfigurationoptionhadbeenchangedtoNo.,AsimplefixforthisistoaddtheUseDNSoptiontothesshd_configandtosetittono.Thiscaneasilybedone ...,2019年2月7日—UseDNSSpecifieswhethersshd(8)shouldlookuptheremotehostname,andtocheckthattheresolvedhostnamefortheremoteIPaddressmaps ...,2014年7月25日—I'dproposetomakethedefaultsettingforUseDNSbeNo.F...

參考資訊如下
1478175

2017年8月3日 — In Red Hat Enterprise Linux 7.4, the default value of the UseDNS configuration option had been changed to No.

Add "UseDNS no" option in sshd_config of appliance by default

A simple fix for this is to add the UseDNS option to the sshd_config and to set it to no. This can easily be done ...

Default UseDNS should be "no" in sshd_config · Issue #267

2019年2月7日 — UseDNS Specifies whether sshd(8) should look up the remote host name, and to check that the resolved host name for the remote IP address maps ...

Default useDNS to be 'No' on sshd_config · Issue #92

2014年7月25日 — I'd propose to make the default setting for UseDNS be No . From the manpage of sshd_config(5) : UseDNS Specifies whether sshd(8) should look up ...

sshd_config(5)

The default value for RekeyLimit is default none, which means that rekeying ... UseDNS Specifies whether sshd(8) should look up the remote host name, and to ...

sshd tries reverse DNS lookups with UseDNS no

2014年2月17日 — I tried to add -u0 to /etc/default/ssh, but it doesn't seem to have changed anything. I'm out of ideas at this point, any suggestion will be ...

What is the point of sshd “UseDNS” option?

2012年11月27日 — The default is “yes”. Enabling this makes access from a location without proper (forward and reverse) DNS generate a warning in the logs. So ...

Using UseDNS to enable SSH slows down SSH logon or ...

2022年3月31日 — The UseDNS feature is a security enhancement feature of SSH. It is not enabled by default. After reverse lookup is enabled, the server ...

UseDNS option

The default value for the UseDNS option changed from yes to no. With this change, sshd no longer converts a client's IP address back into a host name.

解決SSH 登入很慢、很久的問題

2017年12月30日 — SSH 連線到某些機器，有時候會等超過5 秒，有一個原因就是UseDNS 這個 ... The default is ''yes''. 修改SSH daemon 設定. Mac 系統的設定檔： /etc ...