Внезапно обнаружил, что IOS с незапамятных времён умеет SSI.
R1#more flash:test.shtml
R2#telnet 192.168.74.101 80
Trying 192.168.74.101, 80 ... Open
GET /flash/test.shtml HTTP/1.0
HTTP/1.1 200 OK
Date: Fri, 01 Mar 2002 01:16:13 GMT
Server: cisco-IOS
Content-Type: text/html
Expires: Fri, 01 Mar 2002 01:16:13 GMT
Last-Modified: Fri, 01 Mar 2002 01:16:13 GMT
Cache-Control: no-store, no-cache, must-revalidate
Pragma: no-cache
Accept-Ranges: none
R2 uptime is 1 hour, 16 minutes
[Connection to 192.168.74.101 closed by foreign host]
R2#telnet 192.168.74.101 80
Trying 192.168.74.101, 80 ... Open
GET /level/15/configure/-/hostname/R3 HTTP/1.0
HTTP/1.1 200 OK
Date: Fri, 01 Mar 2002 01:17:51 GMT
Server: cisco-IOS
Content-Type: text/html
Expires: Fri, 01 Mar 2002 01:17:51 GMT
Last-Modified: Fri, 01 Mar 2002 01:17:51 GMT
Cache-Control: no-store, no-cache, must-revalidate
Pragma: no-cache
Accept-Ranges: none
[..skip..]
[Connection to 192.168.74.101 closed by foreign host]
R3#
Методы и реализация конечно пипец, но для поиграться потянет :)