Sun Java System Web Server 6.1 SP10 Reverse Proxy Plug-in Release Notes

Server Application Functions (SAFs)

The Reverse Proxy plug-in provides the following Server Application Functions (SAFs):

auth-passthrough

The auth-passthrough AuthTrans SAF inspects an incoming HTTP request for client information encoded by a service-passthrough function running on an intermediate server. The client information includes the following:

The IP address from which the request originated, as encoded in the Proxy-ip header
The SSL/TLS session ID of the originating connection, as encoded in the Proxy-ssl-id header
The SSL/TLS cipher by the originating client, as encoded in the Proxy-cipher, Proxy-keysize, and Proxy-secret-keysize headers
The SSL/TLS client certificate presented by the originating client, as encoded in the Proxy-issuer-dn, Proxy-user-dn, and Proxy-auth-cert headers.

When auth-passthrough detects encoded client information, it instructs the server to treat the request as if it had arrived directly from the originating client instead of through an intermediate server running service-passthrough.

The auth-passthrough SAF is optional. When used, auth-passthrough is used on the server instance that receives the request forwarded by service-passthrough.

Because auth-passthrough makes it possible to override information that may be used for authentication (for example, the IP address of the original request), it is important that only trusted clients and servers be allowed to connect to a server running auth-passthrough. As a minimal precaution, only servers behind a corporate firewall should run auth-passthrough; no internet-accessible server should run auth-passthrough. Further, if information about the originating client is not required, auth-passthrough should not be used.

The following obj.conf code demonstrates the use of auth-passthrough (note that these lines are not indented in a real obj.conf):

<Object name="default"> 
AuthTrans fn="auth-passthrough"
...  
</Object>

check-passthrough

The check-passthrough ObjectType SAF checks to see if the requested resource (for example, the HTML document or GIF image) is available on the local server. If the requested resource does not exist locally, check-passthrough sets the type to indicate that the request should be passed to another server for processing by service-passthrough.

The check-passthrough SAF accepts the following parameters:

type - (Optional) The type to use for files that do not exist locally. If not specified, type defaults to magnus-internal/passthrough.

service-passthrough

The service-passthrough Service SAF forwards a request to another server for processing.

You can configure the number of times the service-passthrough directive tries to get a content from the web server before sending an error to the client by modifying the retries attribute in obj.conf:

<Object name="passthrough">
ObjectType fn="force-type" type="magnus-internal/passthrough"
Service type="magnus-internal/passthrough" fn="service-passthrough"
servers="http://xxx:8084/" poll-timeout="18000" retries="0"
Error reason="Bad Gateway" fn="send-error"
uri="/opt/iplanet/web41sp8/docs/badgateway.html"
</Object>

The service-passthrough SAF accepts the following parameters:

servers - A quoted, space-delimited list of the servers that receive the forwarded requests. Individual server names may optionally be prefixed with http:// or https:// to indicate the protocol and suffixed with a colon and integer to indicate the port.
poll-timeout - Indicates the maximum time interval between two successive data for a single request. It is the waiting period for data to arrive from the client or the server. Reverse proxy plug-in waits for data to arrive from the client or the server. If there is no data written by either client or server, for poll-timeout interval, then the server logs an error and closes the connection. By default, the poll-timeout value is set to 5 minutes but can range between 1 second to 6 hours. poll-timeout does not represent maximum response time, as it could be much higher than poll-timeout value.
sticky-cookie - (Optional) The name of a cookie that will cause requests from a given client to stick to a particular server. Once a request containing a cookie with this name is forwarded to a given server, service-passthrough attempts to forward subsequent requests from that client to the same server by sending a JROUTE header back to the client. If not specified, sticky-cookie defaults to JSESSIONID.
user - (Optional) The username that service-passthrough uses to authenticate to the remote server through Basic-Auth.

Note –
‘user&rsquo' requires that ‘password’ also be specified.
password - (Optional) The password that service-passthrough uses to authenticate to the remote server via Basic-Auth.

Note –
‘password’ requires that ‘user’ also be specified.
client-cert-nickname - (Optional) Nickname of the client certificate that service-passthrough uses to authenticate to the remote server.
validate-server-cert - (Optional) Indicates whether service-passthrough should validate the certificate presented by the remote server. If not specified, validate-server-cert defaults to true.
rewrite-host - (Optional) Indicates whether service-passthrough should rewrite the Host header sent to remote servers, replacing the local server’s hostname with the remote server’s hostname. If not specified, rewrite-host defaults to false.
rewrite-location - (Optional) Indicates whether service-passthrough should rewrite the Location headers returned by a remote server, replacing the remote server’s scheme and hostname with the local server’s scheme and hostname. If not specified, rewrite-location defaults to true.
ip-header - (Optional) Name of the header that contains the client’s IP address, or “” if the IP address should not be forwarded. If not specified, ip-header defaults to Proxy-ip.
cipher-header - (Optional) Name of the header that contains the symmetric cipher used to communicate with the client (when SSL/TLS is used), or “” if the symmetric cipher name should not be forwarded. If not specified, cipher-header defaults to Proxy-cipher.
keysize-header - (Optional) Name of the header that contains the symmetric key size used to communicate with the client (when SSL/TLS is used), or “” if the symmetric key size name should not be forwarded. If not specified, keysize-header defaults to Proxy-keysize.
secret-keysize-header - (Optional) Name of the header that contains the effective symmetric key size used to communicate with the client (when SSL/TLS is used), or “” if the effective symmetric key size name should not be forwarded. If not specified, secret-keysize-header defaults to Proxy-secret-keysize.
ssl-id-header - (Optional) Name of the header that contains the client’s SSL/TLS session ID (when SSL/TLS is used), or “” if the SSL/TLS session ID should not be forwarded. If not specified, ssl-id-header defaults to Proxy-ssl-id.
issuer-dn-header - (Optional) Name of the header that contains the client certificate issuer DN (when SSL/TLS is used), or “” if the client certificate issuer DN should not be forwarded. If not specified, issuer-dn-header defaults to Proxy-issuer-dn.
user-dn-header - (Optional) Name of the header that contains the client certificate user DN (when SSL/TLS is used), or “” if the client certificate user DN should not be forwarded. If not specified, user-dn-header defaults to Proxy-user-dn.
auth-cert-header - (Optional) Name of the header that contains the DER-encoded client certificate in Base64 encoding (when SSL/TLS is used), or “” if the client certificate should not be forwarded. If not specified, auth-cert-header defaults to Proxy-auth-cert.

When multiple remote servers are configured, service-passthrough chooses a single remote server from the list on a request-by-request basis. If a remote server cannot be contacted or returns an invalid response, service-passthrough sets the status code to 502 Bad Gateway and returns REQ_ABORTED. This will return an error to the browser. This error can be customized in the Web Server by configuring a customized response for the 502 error code.

When user and password are specified, service-passthrough will use these credentials to authenticate to the remote server using HTTP basic authentication. When one or more of the servers in the servers parameter are configured with a https:// prefix, client-cert-nickname specifies the nickname of the client certificate service-passthrough will use to authenticate to the remote server.

Note –

service-passthrough generally uses HTTP/1.1 and persistent connections for outbound requests with the following exceptions:

When forwarding a request with a Range header that arrived through HTTP/1.0, service-passthrough issues an HTTP/1.0 request. This is done because the experimental Range semantics expected by Netscape HTTP/1.0 clients differ from the Range semantics defined by the HTTP/1.1 specification.
When forwarding a request with a request body (For example POST request), service-passthrough will not reuse an existing persistent connection. This is done because the remote server is free to close a persistent connection at any time, and service-passthrough will not retry requests with a request body.

In addition, service-passthrough encodes information about the originating client in the headers named by the ip-header, cipher-header, keysize-header, secret-keysize-header, ssl-id-header, issuer-dn-header, user-dn-header, and auth-cert-headerparameters (removing any client-supplied headers with the same name) before forwarding the request. Applications running on the remote server may examine these headers to extract information about the originating client.