060win2000_1.htm

来自「鸟哥LINUX 学习课本」· HTM 代码 · 共 697 行 · 第 1/5 页

HTM
697
字号
	28 </SPAN></FONT>才是我们所需要的<FONT FACE="Tahoma, serif"><SPAN LANG="en-US">	MTU </SPAN></FONT>值!所以,在上面的例子中,我们<FONT COLOR="#3333ff">所需要的<FONT FACE="Tahoma, serif"><SPAN LANG="en-US">	MTU </FONT></SPAN></FONT><FONT COLOR="#3333ff">值是<FONT FACE="Tahoma, serif"><SPAN LANG="en-US">	1464+28=1492 </FONT></SPAN></FONT>啦!<FONT FACE="Tahoma, serif"><SPAN LANG="en-US">	</SPAN></FONT>	</BLOCKQUOTE></UL><UL>	<LI><BLOCKQUOTE><FONT COLOR="#3333ff">修改<FONT FACE="Tahoma, serif"><SPAN LANG="en-US">	MTU </FONT></SPAN></FONT><FONT COLOR="#3333ff">值:</FONT><FONT FACE="Tahoma, serif"><SPAN LANG="en-US">	<BR>OK</SPAN></FONT>!我们已经找出<FONT FACE="Tahoma, serif"><SPAN LANG="en-US">	MTU </SPAN></FONT>值啦,那下一步自然就是修改罗!要如何修改呢?其实也是很简单,只要通过<FONT FACE="Tahoma, serif"><SPAN LANG="en-US">	Windows </SPAN></FONT>本身缺省的<FONT FACE="Tahoma, serif"><SPAN LANG="en-US">	registry </SPAN></FONT>修改即可!<FONT FACE="Tahoma, serif"><SPAN LANG="en-US">	</SPAN></FONT>	</BLOCKQUOTE></UL><UL>	<BLOCKQUOTE STYLE="margin-bottom: 0cm"><FONT FACE="Tahoma, serif"><SPAN LANG="en-US"><FONT COLOR="#000099">Windows	98</FONT></SPAN></FONT><FONT COLOR="#000099">:</FONT><FONT FACE="Tahoma, serif"><SPAN LANG="en-US">	</SPAN></FONT>	</BLOCKQUOTE>	<OL>		<LI><BLOCKQUOTE STYLE="margin-bottom: 0cm">在<FONT FACE="Tahoma, serif"><SPAN LANG="en-US">		</SPAN></FONT>『开始』<FONT FACE="Tahoma, serif"><SPAN LANG="en-US">&gt;</SPAN></FONT>『运行』中,键入<FONT FACE="Tahoma, serif"><SPAN LANG="en-US">&lt;regedit&gt;</SPAN></FONT>,会出现一个大框框;<FONT FACE="Tahoma, serif"><SPAN LANG="en-US">		</SPAN></FONT>		</BLOCKQUOTE>		<LI><BLOCKQUOTE STYLE="margin-bottom: 0cm">选择:『<FONT FACE="Tahoma, serif"><SPAN LANG="en-US">HKEY_Local_Machine</SPAN></FONT>』<FONT FACE="Tahoma, serif"><SPAN LANG="en-US">&gt;</SPAN></FONT>『<FONT FACE="Tahoma, serif"><SPAN LANG="en-US">System</SPAN></FONT>』<FONT FACE="Tahoma, serif"><SPAN LANG="en-US">&gt;</SPAN></FONT>『<FONT FACE="Tahoma, serif"><SPAN LANG="en-US">CurrentControlSet</SPAN></FONT>』<FONT FACE="Tahoma, serif"><SPAN LANG="en-US">&gt;</SPAN></FONT>『<FONT FACE="Tahoma, serif"><SPAN LANG="en-US">Services</SPAN></FONT>』<FONT FACE="Tahoma, serif"><SPAN LANG="en-US">&gt;</SPAN></FONT>『<FONT FACE="Tahoma, serif"><SPAN LANG="en-US">Class</SPAN></FONT>』<FONT FACE="Tahoma, serif"><SPAN LANG="en-US">&gt;</SPAN></FONT>『<FONT FACE="Tahoma, serif"><SPAN LANG="en-US">NetTrans</SPAN></FONT>』<FONT FACE="Tahoma, serif"><SPAN LANG="en-US">&gt;</SPAN></FONT>『<FONT FACE="Tahoma, serif"><SPAN LANG="en-US">000n</SPAN></FONT>』<FONT FACE="Tahoma, serif"><SPAN LANG="en-US">		<BR></SPAN></FONT>上面<FONT COLOR="#3333ff">最后一个数据是<FONT FACE="Tahoma, serif"><SPAN LANG="en-US">		000n</FONT></SPAN></FONT><FONT COLOR="#3333ff">,那个<FONT FACE="Tahoma, serif"><SPAN LANG="en-US">		n </FONT></SPAN></FONT><FONT COLOR="#3333ff">指的是数字</FONT>,以我为例,在<FONT FACE="Tahoma, serif"><SPAN LANG="en-US">		NetTrans </SPAN></FONT>底下有两个数字,分别为<FONT FACE="Tahoma, serif"><SPAN LANG="en-US">		0000 </SPAN></FONT>与<FONT FACE="Tahoma, serif"><SPAN LANG="en-US">		0002</SPAN></FONT>,若按下<FONT FACE="Tahoma, serif"><SPAN LANG="en-US">		0000 </SPAN></FONT>会显示我的<FONT FACE="Tahoma, serif"><SPAN LANG="en-US">		Gate Way </SPAN></FONT>以及我的网络卡的<FONT FACE="Tahoma, serif"><SPAN LANG="en-US">		IP </SPAN></FONT>项目,至于<FONT FACE="Tahoma, serif"><SPAN LANG="en-US">		0002 </SPAN></FONT>则没有我的网络卡的相关信息,所以<FONT FACE="Tahoma, serif"><SPAN LANG="en-US">		0000 </SPAN></FONT>那这一个就是我的网络卡接口啦!请依你的情况选择!<FONT FACE="Tahoma, serif"><SPAN LANG="en-US">		</SPAN></FONT>		</BLOCKQUOTE>		<LI><BLOCKQUOTE STYLE="margin-bottom: 0cm">选择你的网络卡接口后(以我为例,单击<FONT FACE="Tahoma, serif"><SPAN LANG="en-US">		0000 </SPAN></FONT>那一个机代码),按下『编辑』<FONT FACE="Tahoma, serif"><SPAN LANG="en-US">&gt;</SPAN></FONT>『新增』,然后选择增加『<FONT FACE="Tahoma, serif"><SPAN LANG="en-US">DWORD</SPAN></FONT>』值;<FONT FACE="Tahoma, serif"><SPAN LANG="en-US">		</SPAN></FONT>		</BLOCKQUOTE>		<OL>			<BLOCKQUOTE STYLE="margin-bottom: 0cm"><IMG SRC="060win2000_1_files/16win2000_1-mtu1.jpg" NAME="图形19" ALIGN=BOTTOM WIDTH=342 HEIGHT=126 BORDER=0></BLOCKQUOTE>		</OL>		<LI><BLOCKQUOTE STYLE="margin-bottom: 0cm">将新增的机代码取名为『<FONT FACE="Tahoma, serif"><SPAN LANG="en-US">MaxMTU</SPAN></FONT>』,并且在新增加的那个机代码上面按右键,选『修改』,会出现如下屏面,选择『十进制』后,输入刚刚我们找到的那一个<FONT FACE="Tahoma, serif"><SPAN LANG="en-US">		MTU </SPAN></FONT>值:<FONT FACE="Tahoma, serif"><SPAN LANG="en-US">		</SPAN></FONT>		</BLOCKQUOTE>		<OL>			<BLOCKQUOTE STYLE="margin-bottom: 0cm"><IMG SRC="060win2000_1_files/16win2000_1-mtu2.jpg" NAME="图形20" ALIGN=BOTTOM WIDTH=322 HEIGHT=200 BORDER=0></BLOCKQUOTE>		</OL>		<LI><BLOCKQUOTE STYLE="margin-bottom: 0cm">改完之后你应该会看到如下的屏面喔!那就是成功了!<FONT FACE="Tahoma, serif"><SPAN LANG="en-US">		</SPAN></FONT>		</BLOCKQUOTE>		<OL>			<BLOCKQUOTE><IMG SRC="060win2000_1_files/16win2000_1-mtu3.jpg" NAME="图形21" ALIGN=BOTTOM WIDTH=251 HEIGHT=74 BORDER=0></BLOCKQUOTE>		</OL>	</OL></UL><UL>	<BLOCKQUOTE STYLE="margin-bottom: 0cm"><FONT FACE="Tahoma, serif"><SPAN LANG="en-US"><FONT COLOR="#000099">Windows	2000</FONT></SPAN></FONT><FONT COLOR="#000099">:</FONT><FONT FACE="Tahoma, serif"><SPAN LANG="en-US">	</SPAN></FONT>	</BLOCKQUOTE>	<OL>		<LI><BLOCKQUOTE STYLE="margin-bottom: 0cm">在<FONT FACE="Tahoma, serif"><SPAN LANG="en-US">		</SPAN></FONT>『开始』<FONT FACE="Tahoma, serif"><SPAN LANG="en-US">&gt;</SPAN></FONT>『运行』中,键入<FONT FACE="Tahoma, serif"><SPAN LANG="en-US">&lt;regedit&gt;</SPAN></FONT>,会出现一个大框框(注意,也有可能是<FONT FACE="Tahoma, serif"><SPAN LANG="en-US">		regedit32 </SPAN></FONT>这个运行档,请依你的机器来操作);<FONT FACE="Tahoma, serif"><SPAN LANG="en-US">		</SPAN></FONT>		</BLOCKQUOTE>		<LI><BLOCKQUOTE STYLE="margin-bottom: 0cm">选择『<FONT FACE="Tahoma, serif"><SPAN LANG="en-US">HKEY_Local_Machine</SPAN></FONT>』<FONT FACE="Tahoma, serif"><SPAN LANG="en-US">&gt;</SPAN></FONT>『<FONT FACE="Tahoma, serif"><SPAN LANG="en-US">SYSTEM</SPAN></FONT>』<FONT FACE="Tahoma, serif"><SPAN LANG="en-US">&gt;</SPAN></FONT>『<FONT FACE="Tahoma, serif"><SPAN LANG="en-US">CurrentControlSet</SPAN></FONT>』<FONT FACE="Tahoma, serif"><SPAN LANG="en-US">&gt;</SPAN></FONT>『<FONT FACE="Tahoma, serif"><SPAN LANG="en-US">Services</SPAN></FONT>』<FONT FACE="Tahoma, serif"><SPAN LANG="en-US">&gt;</SPAN></FONT>『<FONT FACE="Tahoma, serif"><SPAN LANG="en-US">Tcpip</SPAN></FONT>』<FONT FACE="Tahoma, serif"><SPAN LANG="en-US">&gt;</SPAN></FONT>『<FONT FACE="Tahoma, serif"><SPAN LANG="en-US">Parameters</SPAN></FONT>』<FONT FACE="Tahoma, serif"><SPAN LANG="en-US">&gt;</SPAN></FONT>『<FONT FACE="Tahoma, serif"><SPAN LANG="en-US">interface</SPAN></FONT>』,有点象下面的图示:<FONT FACE="Tahoma, serif"><SPAN LANG="en-US">		</SPAN></FONT>		</BLOCKQUOTE>		<OL>			<BLOCKQUOTE STYLE="margin-bottom: 0cm"><IMG SRC="060win2000_1_files/16win2000_1-mtu4.jpg" NAME="图形22" ALIGN=BOTTOM WIDTH=242 HEIGHT=160 BORDER=0></BLOCKQUOTE>		</OL>		<LI><BLOCKQUOTE>在<FONT FACE="Tahoma, serif"><SPAN LANG="en-US">		interface </SPAN></FONT>底下可能有很多的接口,你一个一个的去看,会有一个接口与你的网络卡的<FONT FACE="Tahoma, serif"><SPAN LANG="en-US">		IP		</SPAN></FONT>相同,那个就是你要挑选的接口啦!然后同样的在该接口上选择『编辑』<FONT FACE="Tahoma, serif"><SPAN LANG="en-US">&gt;</SPAN></FONT>『新增』<FONT FACE="Tahoma, serif"><SPAN LANG="en-US">&gt;</SPAN></FONT>『<FONT FACE="Tahoma, serif"><SPAN LANG="en-US">DWORD</SPAN></FONT>值』之后,创建一个名为『<FONT FACE="Tahoma, serif"><SPAN LANG="en-US"><FONT COLOR="#3333ff">MTU</FONT></SPAN></FONT>』的机代码,然后选右键『修改』,选择十进制,填入我们刚刚找出来的<FONT FACE="Tahoma, serif"><SPAN LANG="en-US">		MTU </SPAN></FONT>值!大功告成!<FONT FACE="Tahoma, serif"><SPAN LANG="en-US">		</SPAN></FONT>		</BLOCKQUOTE>	</OL></UL><BLOCKQUOTE>基本上,这样应该已经可以解决你的问题了!相关的网页你可以到底下两个网页去看看!<FONT FACE="Tahoma, serif"><SPAN LANG="en-US"><BR><A HREF="http://www.microsoft.com/taiwan/msclub/member/TIPS/Spring_2001/tip1to3/tip1to3_2.htm" TARGET="_blank">http://www.microsoft.com/taiwan/msclub/member/TIPS/Spring_2001/tip1to3/tip1to3_2.htm</A><BR><A HREF="http://redhat.ecenter.idv.tw/bbs/showthread.php?s=&amp;threadid=21620&amp;highlight=MTU" TARGET="_blank">http://redhat.ecenter.idv.tw/bbs/showthread.php?s=&amp;threadid=21620&amp;highlight=MTU</A></SPAN></FONT></BLOCKQUOTE><UL>	<P>另外,网友有建议另一个测试<FONT FACE="Tahoma, serif"><SPAN LANG="en-US">	MTU </SPAN></FONT>的网页,你也可以上去瞧一瞧,不过,要上这个网页之前,『<FONT COLOR="#3333ff">请先将你的<FONT FACE="Tahoma, serif"><SPAN LANG="en-US">	</FONT></SPAN></FONT><FONT COLOR="#3333ff">代理服务器设定<FONT FACE="Tahoma, serif"><SPAN LANG="en-US">	</FONT></SPAN></FONT><FONT COLOR="#3333ff">取消</FONT>』否则测到的会是你的<FONT FACE="Tahoma, serif"><SPAN LANG="en-US">	Proxy </SPAN></FONT>而不是你的真实<FONT FACE="Tahoma, serif"><SPAN LANG="en-US">	IP </SPAN></FONT>喔!<FONT FACE="Tahoma, serif"><SPAN LANG="en-US">	<BR><A HREF="http://forums.speedguide.net:8117/" TARGET="_blank">http://forums.speedguide.net:8117/</A></SPAN></FONT></P></UL><UL>	<P STYLE="margin-bottom: 0cm">此外,网友『许先生』来信告知小弟对于<FONT FACE="Tahoma, serif"><SPAN LANG="en-US">	MTU </SPAN></FONT>的认知可能较为不足,底下将许先生的来信附在文末,希望对大家有点帮助:<FONT FACE="Tahoma, serif"><SPAN LANG="en-US">	<BR>&nbsp; </SPAN></FONT>	</P></UL><DL>	<DD>	<TABLE COLS=1 WIDTH=90% BORDER=1 CELLPADDING=2 CELLSPACING=2 BGCOLOR="#cccccc">		<TR>			<TD>				<P>你好:<FONT FACE="Tahoma, serif"><SPAN LANG="en-US"> </SPAN></FONT>				</P>				<P>在拜读了先生的站点关于<FONT FACE="Tahoma, serif"><SPAN LANG="en-US">MTU</SPAN></FONT>的文章之后<FONT FACE="Tahoma, serif"><SPAN LANG="en-US">,</SPAN></FONT>对于其中某些部分有点小评论<FONT FACE="Tahoma, serif"><SPAN LANG="en-US">,</SPAN></FONT>在此提交以供参考<FONT FACE="Tahoma, serif"><SPAN LANG="en-US">,</SPAN></FONT>若有错误也还请指教:<FONT FACE="Tahoma, serif"><SPAN LANG="en-US">				<BR>MTU</SPAN></FONT>并不是越大越好<FONT FACE="Tahoma, serif"><SPAN LANG="en-US">,</SPAN></FONT>也不是越小越好<FONT FACE="Tahoma, serif"><SPAN LANG="en-US">.</SPAN></FONT>应说是看你的网络来作优化<FONT FACE="Tahoma, serif"><SPAN LANG="en-US">.</SPAN></FONT>假设<FONT FACE="Tahoma, serif"><SPAN LANG="en-US">MTU</SPAN></FONT>非常大<FONT FACE="Tahoma, serif"><SPAN LANG="en-US">,</SPAN></FONT>就好比一台车可以坐<FONT FACE="Tahoma, serif"><SPAN LANG="en-US">1500</SPAN></FONT>人<FONT FACE="Tahoma, serif"><SPAN LANG="en-US">,</SPAN></FONT>但是现在总共有<FONT FACE="Tahoma, serif"><SPAN LANG="en-US">3001				</SPAN></FONT>个人<FONT FACE="Tahoma, serif"><SPAN LANG="en-US">,</SPAN></FONT>你必须开<FONT FACE="Tahoma, serif"><SPAN LANG="en-US">3</SPAN></FONT>台车<FONT FACE="Tahoma, serif"><SPAN LANG="en-US">,</SPAN></FONT>其中一台虽然可以载<FONT FACE="Tahoma, serif"><SPAN LANG="en-US">1500</SPAN></FONT>人<FONT FACE="Tahoma, serif"><SPAN LANG="en-US">,</SPAN></FONT>但是却只有一个人在使用<FONT FACE="Tahoma, serif"><SPAN LANG="en-US">,</SPAN></FONT>浪费了<FONT FACE="Tahoma, serif"><SPAN LANG="en-US">1499</SPAN></FONT>个资源<FONT FACE="Tahoma, serif"><SPAN LANG="en-US">.</SPAN></FONT>如果是有一部车可坐<FONT FACE="Tahoma, serif"><SPAN LANG="en-US">150</SPAN></FONT>人的话<FONT FACE="Tahoma, serif"><SPAN LANG="en-US">,</SPAN></FONT>那幺同样<FONT FACE="Tahoma, serif"><SPAN LANG="en-US">				3001</SPAN></FONT>人<FONT FACE="Tahoma, serif"><SPAN LANG="en-US">,</SPAN></FONT>需<FONT FACE="Tahoma, serif"><SPAN LANG="en-US">21</SPAN></FONT>台车<FONT FACE="Tahoma, serif"><SPAN LANG="en-US">,</SPAN></FONT>但是却只浪费<FONT FACE="Tahoma, serif"><SPAN LANG="en-US">149</SPAN></FONT>个位置<FONT FACE="Tahoma, serif"><SPAN LANG="en-US">,</SPAN></FONT>以此类推<FONT FACE="Tahoma, serif"><SPAN LANG="en-US">,</SPAN></FONT>似乎是越小越好<FONT FACE="Tahoma, serif"><SPAN LANG="en-US">.</SPAN></FONT>实际上也不尽然<FONT FACE="Tahoma, serif"><SPAN LANG="en-US">,</SPAN></FONT>因为每个封包都有一些档头之类其他供人识别的数据<FONT FACE="Tahoma, serif"><SPAN LANG="en-US">,</SPAN></FONT>所以<FONT FACE="Tahoma, serif"><SPAN LANG="en-US">				</SPAN></FONT>内容是<FONT FACE="Tahoma, serif"><SPAN LANG="en-US">1500,</SPAN></FONT>但是前面所提的档头<FONT FACE="Tahoma, serif"><SPAN LANG="en-US">,</SPAN></FONT>却也要<FONT FACE="Tahoma, serif"><SPAN LANG="en-US">18,</SPAN></FONT>所以总共是<FONT FACE="Tahoma, serif"><SPAN LANG="en-US">1518</SPAN></FONT>才是正确的<FONT FACE="Tahoma, serif"><SPAN LANG="en-US">.				</SPAN></FONT>				</P>				<P>假设封包内容都是非常小<FONT FACE="Tahoma, serif"><SPAN LANG="en-US">,</SPAN></FONT>反而那些占<FONT FACE="Tahoma, serif"><SPAN LANG="en-US">18</SPAN></FONT>的档头会重复浪费<FONT FACE="Tahoma, serif"><SPAN LANG="en-US">.</SPAN></FONT>所以切的越小<FONT FACE="Tahoma, serif"><SPAN LANG="en-US">,</SPAN></FONT>就好比只有几个人坐飞机<FONT FACE="Tahoma, serif"><SPAN LANG="en-US">,</SPAN></FONT>但是机上的服务人员等<FONT FACE="Tahoma, serif"><SPAN LANG="en-US">,</SPAN></FONT>都比乘客还多<FONT FACE="Tahoma, serif"><SPAN LANG="en-US">.</SPAN></FONT>因此<FONT FACE="Tahoma, serif"><SPAN LANG="en-US">MTU</SPAN></FONT>不是越大越好<FONT FACE="Tahoma, serif"><SPAN LANG="en-US">,</SPAN></FONT>也不是越小越好&nbsp;</P>			</TD>		</TR>		<TR>			<TD>				<P>刚刚看了其他部分<FONT FACE="Tahoma, serif"><SPAN LANG="en-US">,</SPAN></FONT>好象<FONT FACE="Tahoma, serif"><SPAN LANG="en-US">NAT</SPAN></FONT>的地方和小弟所知有一点不一样<FONT FACE="Tahoma, serif"><SPAN LANG="en-US">,</SPAN></FONT>在<FONT FACE="Tahoma, serif"><SPAN LANG="en-US">win2k</SPAN></FONT>的设定网络共享部分<FONT FACE="Tahoma, serif"><SPAN LANG="en-US">,</SPAN></FONT>那不是<FONT FACE="Tahoma, serif"><SPAN LANG="en-US">NAT.</SPAN></FONT>你应该是用<FONT FACE="Tahoma, serif"><SPAN LANG="en-US">				professional</SPAN></FONT>吧<FONT FACE="Tahoma, serif"><SPAN LANG="en-US">,</SPAN></FONT>其实在<FONT FACE="Tahoma, serif"><SPAN LANG="en-US">server</SPAN></FONT>版的设定中有一项<FONT FACE="Tahoma, serif"><SPAN LANG="en-US">,</SPAN></FONT>在路由及远程访问才是喔<FONT FACE="Tahoma, serif"><SPAN LANG="en-US">.</SPAN></FONT>在贵网页所提的是<FONT FACE="Tahoma, serif"><SPAN LANG="en-US">ICS,</SPAN></FONT>那只可以设定在<FONT FACE="Tahoma, serif"><SPAN LANG="en-US">				192.168.0.x</SPAN></FONT>这个网段<FONT FACE="Tahoma, serif"><SPAN LANG="en-US">,</SPAN></FONT>也所以只可以分享到<FONT FACE="Tahoma, serif"><SPAN LANG="en-US">253</SPAN></FONT>台<FONT FACE="Tahoma, serif"><SPAN LANG="en-US">,</SPAN></FONT>其实所谓<FONT FACE="Tahoma, serif"><SPAN LANG="en-US">NAT</SPAN></FONT>是网络地址之间的转换<FONT FACE="Tahoma, serif"><SPAN LANG="en-US">,</SPAN></FONT>不一定是真实<FONT FACE="Tahoma, serif"><SPAN LANG="en-US">ip</SPAN></FONT>转换到虚拟<FONT FACE="Tahoma, serif"><SPAN LANG="en-US">ip,</SPAN></FONT>也可以是虚拟<FONT FACE="Tahoma, serif"><SPAN LANG="en-US">ip				</SPAN></FONT>转换到虚拟<FONT FACE="Tahoma, serif"><SPAN LANG="en-US">ip,</SPAN></FONT>象<FONT FACE="Tahoma, serif"><SPAN LANG="en-US">class				a</SPAN></FONT>转换到<FONT FACE="Tahoma, serif"><SPAN LANG="en-US">class				c.</SPAN></FONT>所以严格说来<FONT FACE="Tahoma, serif"><SPAN LANG="en-US">ICS</SPAN></FONT>算是<FONT FACE="Tahoma, serif"><SPAN LANG="en-US">NAT</SPAN></FONT>的一种<FONT FACE="Tahoma, serif"><SPAN LANG="en-US">,</SPAN></FONT>但是并不是真正的<FONT FACE="Tahoma, serif"><SPAN LANG="en-US">NAT.</SPAN></FONT></P>			</TD>		</TR>	</TABLE></DL><P STYLE="margin-bottom: 0cm"><FONT FACE="Tahoma, serif">

⌨️ 快捷键说明

复制代码Ctrl + C
搜索代码Ctrl + F
全屏模式F11
增大字号Ctrl + =
减小字号Ctrl + -
显示快捷键?