Spell check.

www/security.html

@@ -35,7 +35,7 @@ that in your browser.
 
 <p>
 To protect data you submit, SSL is used to encrypt data as it
-is transferred accross the Internet. Therefore, you will need to
+is transferred across the Internet. Therefore, you will need to
 access these pages with a browser that supports SSL.  We recommend
 Netscape 4.0 or later, or presumably a recent IE.
 </p>
@@ -114,7 +114,7 @@ at other sites.
 Emulab blocks incoming connections to nodes on all of the <i>low numbered</i> ports
 (ports below 1024), with the
 exception of ports 20 and 21 (FTP), 22 (Secure Shell), and 80 (HTTP). This is
-for the protection of experimentors, as well help prevent an errant
+for the protection of experimenters, as well help prevent an errant
 application from becoming the source of a Denial of Service attack to sites
 outside of Emulab. If your application requires external access to other low
 numbered ports, please contact us to make special arrangements.
@@ -137,9 +137,9 @@ want your nodes to be able to function as "normal" Emulab nodes.
 </p>
 
 <p>
-In the table below, a direction of 'out' measn that your node needs to be able
+In the table below, a direction of 'out' means that your node needs to be able
 to make outgoing TCP connections to a port, 'in' means that it needs to accept
-incoming connections on a port, and 'both' indcates UDP ports on which you must
+incoming connections on a port, and 'both' indicates UDP ports on which you must
 be able to send out packets and receive the replies.
 </p>
 
@@ -208,7 +208,7 @@ default directory permissions are set so that project files are not
 readable by members of other projects.
 </p>
 <p>
-Each project gets its own directory hierachy (again, protected by the
+Each project gets its own directory hierarchy (again, protected by the
 Unix group mechanism) that is NFS-exported only to that project's
 assigned test machines.  We don't currently protect against spoofing
 on the control network, so there are vulnerabilities.  The test