|PageViews: 176 / 171 / 133 hits / 30 nets since Jun 30 2020|
COUNTER parameter == COUNTER=listOfCounterControl counterControl == do | total | acc | ssi | ref | err | ro | no | mntpV -- default: COUNTER=no -- restriction: applicable to HTTP, SMTP, FTP and DNS
Each access counter is stored in a file at "ADMDIR/counts/access/URL#count". Each counter file starts with a line consists of the numbers of accesses in ASCII decimal format so that it can be initialized or modified manually. The line can contain three numbers; the first one is the total count, the second one is the count excluding repetitive accesses from the same client, and the third one is the count excluding repetitive access from one of recent ten clients. Each count are represented as %T, %U and %V respectively in the format string described below.
The counter can be displayed in a specified format using SSI as the PAGE_COUNT or COUNTER value. If no "url" attribute is specified in a tag, the URL of the SHTML file containing the tag is implied. Counter values are converted to a printable character string following to the format string given in the "fmt=..." attribute. The default format is "%T".
The total count is displayed by TOTAL_HITS tag or by COUNTER tag with "sel=total". The referrer counter of a URL is incremented when the URL is in "Referer:" header in a HTTP request. Each referrer counter is stored in a file at "ADMDIR/counts/referer/URL#count-ref". The referrer counter can be displayed with "sel=ref" attribute in the COUNTER tag.
Enabling all counters for each URL can be expensive and/or unnecessary. You can reduce counters by using the counter of a MOUNT point as the representative, or using only total access counters of the server. In the following example, counters for all URLs is enabled by default (with COUNTER=do), while counters for URLs under /srv1/ is represented by the counter of /srv1/, and only the server's total counter and SSI counters are enabled for URLs under /mine/. As shown in this example, COUNTER can be specified as a MountOption of which initial value is inherited from the COUNTER parameter.
COUNTER=do MOUNT="/srv1/* http://srv1/* COUNTER=mntpV" MOUNT="/mine/* file:dirpath/* COUNTER=no,total,ssi"
Server Side Include in SHTML files
Note that including a resource by SSI is under the access control of
DeleGate (as origin or proxy server) common to the access control
against client users. That is, if a client user is forbidden to
access the included resource, it is also forbidden even via SSI-include.
Especially allowing including a resource out of the DeleGate server, with URL like virtual=http://exserver/dir/fileX can make a security hole made by a user as a SHTML writer. In an origin server, relaying as a proxy must be forbidden by RELAY=no, but it also forbids SSI-include to do from other servers.
A simple workaround in version 9 is adding a limited RELAY as RELAY="proxy:http:exserver:*" that only allows relaying to exserver. Another safer workaround is using MOUNT like MOUNT="/ex/* http://exserver/dir/*" then write SSI-include like virtual="/ex/fileX". But both of these allows client users to access to resources other than the intended virtual URL in the exserver.
To cope with the above problem in version 10, RELAY=ssi is
introduced to be used together with RELAY=no. RELAY=ssi allows
SHTML writers to do include from other servers, leaving the permission
for client users unchanged (as RELAY=no).
In other words without RELAY=ssi, you (as the administrator of DeleGate)
can forbid SHTML writers to include from other servers.
Also you can restrict the includable target server (and protocols or clients)
by the generic notation of DeleGate as
NOTE: Maybe it is impossible to forbid CGIs to access arbitrary servers
in a way independent of platforms and languages.
But at least we can forbid CGIs completely with
Another (and maybe more important) extension in version 10 is relaying request/response message header (as Cookie or User-Agent) back and forth between client and server via SSI-include.
NOTE: Maybe it is impossible to forbid CGIs to access arbitrary servers in a way independent of platforms and languages. But at least we can forbid CGIs completely with REMITTABLE="+,-cgi".