In my January IP Corner article, Keep Track of Router Configurations with Configuration Archive, you'll find in-depth description of the IOS Configuration Archive feature, ways to integrate it with HTTP servers and enhance its functionality with IOS Embedded Event Manager.
I simply had to check with the RFC; by setting the Host: field of HTTP request to an IP address (instead of a host name), Cisco IOS violates section 14.23 of RFC 2616, which says:
The Host request-header field specifies the Internet host and port number of the resource being requested, as obtained from the original URI given by the user or referring resource ... The Host field value MUST represent the naming authority of the origin server or gateway given by the original URL.
If you run multiple web sites on a single physical server, it's highly likely that you rely on the ability of HTTP/1.1 clients to specify the Host: field in the HTTP request to indicate which web site they're trying to access.
Cisco IOS always inserts the web server's IP address (not the hostname) in the Host: field of the HTTP request, regardless of whether you enter IP address or hostname in the URL part of an IOS command that supports HTTP (for example, copy or more command) ... and regardless of whether the hostname is locally configured with the ip host command or resolved by an external DNS server specified in the ip name-server command.
End result: Cisco IOS-based routers (tested up to release 12.4(11)T) can access only the default web site on a web server hosting multiple web sites.
Cisco IOS has the ability to define command aliases - short words that substitute a whole exec-mode or configuration command. These aliases can also be used in command execution URLs. For example, if you define alias exec showdefault show ip route 0.0.0.0 0.0.0.0, you can view the status of the default route with the http://router/exec/showdefault/CR URL.
Another un(der)documented fact: when you access the router's home page (assuming HTTP or HTTPS server has been enabled), the router displays:
Note: even though you can access home.html file on flash: device directly, that web page cannot reference any other file in flash: as a relative link unless you specify flash: as the default path for the HTTP requests with the ip http path flash: command.
These tips will help you get the most out of the Cisco IOS embedded web server:
These ones explain how to use IOS HTTP server and client to manage your router configuration and execute commands on the router:
If you give your users guest access to a router, you might want to disable some web-based applications the router usually offers (for example, command execution). To do this, use the following steps (first supported in IOS release 12.3(14)T, integrated in 12.4):
ip http session-module-list NoExec HTTP_IFS,HOME_PAGE,QDM,QDM_SA,XML_Api,EzVPN-Web-Intercept
I've got a great question related to a previous post:
Is there anyway to send the username and password with the URL request to the router so the user is not prompted for the login?You can specify username and password as part of standard URL syntax http://username:password@host/rest-of-url, so to execute a show ip interface brief command you could use this URL (after configuring multilevel web access on the router):
http://guest:guest@router/level/1/exec/show/ip/interface/briefNote: this syntax no longer works in Internet Explorer with latest security patches, please read http://support.microsoft.com/kb/834489 for more information on how to re-enable this behavior.
In some scenarios you want to use true username/password authentication when accessing the router's web server (by default, you have to use enable password). To change the HTTP authentication method, use the ip http authentication local configuration command; it tells the router to use local usernames and passwords when authentication web requests.
Before changing the HTTP authentication, you must define local usernames with the username username privilege-level level password password command, for example:
username guest privilege 1 password 0 guestNote: unless you configure service password-encryption, the passwords in your configuration will remain in cleartext.
username admin privilege 15 password 0 admin
http://router/level/1/exec/show/users/CRNote: the /CR suffix at the end of the URL tells the router to execute a command that contains optional (non-present) parameters.
If you have HTTP enabled on your router, you can use it to automate router reloads through web requests. To enable HTTP on the router, use the following commands:
ip http serverThe ip http access-class configuration command is vital - it limits the access to the web server on your router to well-defined IP addresses.
ip http access-class 90
access-list 90 permit network-management-ip-address
Const RouterIP = "10.0.0.1" ' replace with router's IP addressAnd here is the equivalent PERL code for the open source community:
Const EnablePassword = "password" ' replace with enable password
Set WebRq = CreateObject("MSXML2.XMLHTTP")
WebRq.Open "GET","http://" & RouterIP & "/level/15/exec/reload/CR",false,"Username",EnablePassword
WebRq.Send
use LWP::UserAgent;By default, the username specified in the web request is ignored by the router and the password has to be the enable password. Of course, if you change the authentication scheme on the router with the ip http authentication configuration command, you'd use proper username/password pair in the HTTP request.
$routerIP = "10.0.0.1";
$enablePwd = "password";
$ua = LWP::UserAgent->new;
$req = HTTP::Request->new(GET => "http://$routerIP/level/15/exec/reload/CR");
$req->authorization_basic('', $enablePwd);
print $ua->request($req)->as_string;
If you've found the description of how to store your router configuration on a web server interesting, you'll probably enjoy the full article documenting the step-by-step solution including the web server configuration.
If you have HTTP server enabled on your router (on by default in many IOS releases, enable with ip http server), you can download the current router configuration into your web browser simply by typing in the URL http://router/exec/show/running/full. To get the startup configuration, use http://router/exec/show/startup-config/CR.
Of course, you need to authenticate to the router. By default, you can use anything as the username and the enable-password as the password, but you also use local usernames or AAA authentication. To use local usernames, configure ip http authentication local and enter username and password with the username username privilege 15 password password configuration command.
ip http client username web-user
ip http client password secret-password
Note: on the web server, you have to configure the target virtual directory for write access (default: disabled) and allow file-system write access to the underlying physical directory for the target user.
router#copy running http://student:lab@192.168.0.2/router-config
Address or name of remote host [192.168.0.2]?
Destination filename [router]?
Storing http://student:lab@192.168.0.2/router-config !!
4231 bytes copied in 0.864 secs (4897 bytes/sec)router#
