topic Re: CSS Forwarding to a down stream CSS in Application Networking

CSS Forwarding to a down stream CSS

simonpope — Tue, 11 Jul 2006 09:41:26 GMT

I have a strange issue that is bugging the hell out of me.

We have around 5 or 6 sites that use the SSL feature of our CSS11501 that work flawlessly. The web servers the CSS forwards to are all directly connected on a subnet hanging off the CSS. I have been asked to setup a new site where by SSL termination occurs on the internet DMZ CSS but then forwards to another CSS (in clear text)that resides in our middleware DMZ (i.e: not a directly connected network). This CSS then load balances to 2 web servers. Internally going direct to the middleware DMZ CSS it works fine.

I have all the service and content rules setup as any other of our sites except the service points to the down stream CSS rather than a directly attached web server. What I am seeing is that a user makes the initial SSL connection to the VIP address and is served up the certificate but then the user then tries to make a direct HTTP connection to the CSS defined as the service address. This is a private address so will never get there.

Here is a basic topology

internet

FW----CSS with SSL (internet DMZ)

FW----CSS (mware DMZ)---web servers

Here is the config.

ssl-proxy-list ssl_accel

ssl-server 7

ssl-server 7 vip address 205.102.196.120

ssl-server 7 rsacert www-placement-cert

ssl-server 7 rsakey www-placement1

ssl-server 7 cipher rsa-with-rc4-128-md5 10.150.149.100 80

ssl-server 7 cipher rsa-with-rc4-128-sha 10.150.149.100 80

active

!************************** SERVICE **************************

service mware-css

protocol tcp

port 80

keepalive type http

keepalive frequency 60

ip address 10.150.149.100

active

service secure-transfer

ip address 2.2.2.2

keepalive type none

type redirect

no prepend-http

redirect-string "https://www.placement-services.com"

active

service ssl_accel

slot 2

type ssl-accel

keepalive type none

add ssl-proxy-list ssl_accel

active

!*************************** OWNER ***************************

owner Placement

content www_placement_http

vip address 205.102.196.120

protocol tcp

port 80

url "/*"

add service secure-transfer

active

content www_placement_ssl

protocol tcp

advanced-balance ssl

port 443

application ssl

vip address 205.102.196.120

add service ssl_accel

active

I suspect the SSL proxy list shouldn't be listing the down stream CSS but I am not sure what else I could point it to??

Thanks in advance for any assistance.

Re: CSS Forwarding to a down stream CSS

skumar1969 — Wed, 12 Jul 2006 00:46:33 GMT

Simon,

See the config below. I just re-arranged your clear-back service and the ssl-proxy-list as well. What I did was I used the command urlrewrite to allow the https to http transition to be a smooth one at the 2nd CSS and used an arbitrary 10.10.10.10 ip address as VIP for the back-end service when the ssl traffic gets decrypted into clear http.

Hope this would work.

ssl-proxy-list ssl_accel

ssl-server 7

ssl-server 7 vip address 205.102.196.120

ssl-server 7 rsacert www-placement-cert

ssl-server 7 rsakey www-placement1

ssl-server 7 cipher rsa-with-rc4-128-md5 10.10.10.10 81

ssl-server 7 urlrewrite 20 placement-services.com

active

!************************** SERVICE **************************

service mware-css

protocol tcp

port 80

keepalive type http

keepalive frequency 60

ip address 10.150.149.100

active

service secure-transfer

ip address 2.2.2.2

keepalive type none

type redirect

no prepend-http

redirect-string "https://www.placement-services.com"

active

service ssl_accel

slot 2

type ssl-accel

keepalive type none

add ssl-proxy-list ssl_accel

active

!*************************** OWNER ***************************

owner Placement

content www_placement_http

vip address 205.102.196.120

protocol tcp

port 80

url "/*"

add service secure-transfer

active

content www_placement_ssl

vip address 205.102.196.120

protocol tcp

port 443

advanced-balance ssl

application ssl

add service ssl_accel

active

content clear-back-mware_CSS

vip address 10.10.10.10

protocol tcp

port 81

url "//placement-services.com/*"

add service mware-css

active

Re: CSS Forwarding to a down stream CSS

simonpope — Wed, 12 Jul 2006 07:02:30 GMT

Thanks for your help. I am now seeing the traffic flow through the fw to the internal CSS. The certificate is being displayed instantaneously on the users PC but a blank page is being returned. Even if I change the mware-css to be one of the actual web servers thus removing the internal CSS a blank page is still displayed. If I access the internal CSS direct it works as expected so I am sure the config internally is OK. I'm getting there but it is just not 100% yet.

Re: CSS Forwarding to a down stream CSS

skumar1969 — Wed, 12 Jul 2006 07:27:26 GMT

Simon,

I pressume you use single interface for the incoming and outgoing traffic between 1st FW and that Internet facing CSS. If yes, on this CSS, you need to allow Source-NAT-ing in addition to the default destination-NAT-ing.

Try adding this config below to the one that I already suggested.

group mware-css

vip address 205.102.196.120

add destination service mware-css

active

Don't forget to:

1/ configure the mware FW to allow packets with source ip 205.102.196.120.

2/ add static route on the Internet-facing-CSS to reach the mware CSS server side circuit's ip subnet.

3/ the mware CSS should have the default gateway configured on it pointing mware firewall.

Hope this would help a bit.

thanks

Re: CSS Forwarding to a down stream CSS

simonpope — Wed, 12 Jul 2006 13:00:25 GMT

Does the config above achieve both source and destination natting? I suspect not. I have confirmed that the mware css receives traffic from the internet css and it can respond to it. for some strange reason users are still displayed a blank page. A TCPDUMP on my firewall shows communication between the internet CSS and the mware CSS one the internet CSS's actual interface IP but the mware CSS communicates on it's VIP address. is this expected behaviour? I would have thought it would be on the internet CSS VIP address??

Re: CSS Forwarding to a down stream CSS

skumar1969 — Wed, 12 Jul 2006 22:47:39 GMT

The config I gave last actually should alter the default behaviour which is dest NAT-ing. Our need at this stage is to have the packets only being Source NAT-ed. My apologies if I sounded wrong earlier.

Reg. the communication between the Internet CSS and the mware CSS, Int.CSS should use its VIP on the Source Group 205.102.196.120 and the mWare CSS should use its VIP under the CR. If there is any deviation if you find just post here the mware CSS config as well.

Try doing an ftp or telnet apart from pinging from each other CSS, and make sure it works and this will tell whether the L3 is connectivity is up or not. Remember when you do the FTP/Telnet the actual circuit ip address would be used and not VIPs as I mentioned above. You might want to open FW gates before that.

thanks