Hi All, We provide proxy services (http/https) to a large number of schools (each with their own static IP). Each school can have 1000's of connections to the virtual server at any time. What we have is a a large squid (proxy) cluster and in front of that is the F5 doing least conns with source address persistence. Each pool member also has a 4000 max conns limit. What we're finding is that several of our squid servers are reaching their max conn limit. 1/ When the max conn limit is reached, will the client (school) request be served by another available pool member taking into consideration that we have source address pesistence enabled so the client (school) is expecting to hit the same pool member all the time? If the client (school) is served by another pool member, wouldn't this then break the source address persistence? 2/ Would something like a OneConnect profile help us reduce the number of connections from the LTM to the squid cluster. I've read up on it but not 100% sure how it applies in a squid/proxy environment. Is this like having one big pipe (tcp connection) from the LTM to the squid box say for school 1's incoming connections, so that all new connections from school 1 uses that big pipe. What about the return traffic from the squid box back to the school? Is it still returning traffic via this big pipe or does it need to create a new tcp connection for the return traffic? Thanks. Andy

Firstly, why do you need to have all the school's connections goto the same squid server? Is this an absolute requirement? Or a nice to have? Yes, oneConnect COULD help you reduce the number of connections... What it's good at doing is to take X connections from clients and multiplex them on Y connections to the backend server. Where in your scenario, Y < X. You'd get more than 1 connections to the squid. It's basically a way of multiplexing hundreds of clients across fewer connections to the backend (Note that this isn't ALL oneconnect does, but it's the one you want). Leaving aside questions of return traffic (Because the LTM will do all this automatically for you), you need to consider the effect of authentication that may occur between the client browser and the proxy (I've seen some scenarios where the webserver only checks the FIRST request and 'assumes' that following requests are the same user... Oops...). You need to get the mask correct for the oneconnect IP address matching too (The only time I really use it is for SSL and bypassing one of the ends that doesn't do HTTP keepalives). In order to answer those questions would require a lot more information... e.g. Do you do authentication? And by what method? H

Posted By Hamish on 03/23/2010 5:38 AM Firstly, why do you need to have all the school's connections goto the same squid server? Is this an absolute requirement? Or a nice to have? This is only in place so that SSL connections goto the same squid box for banking and things like that. We might look at doing SSL persistence and have http traffic load balanced across the squid cluster. Leaving aside questions of return traffic (Because the LTM will do all this automatically for you), you need to consider the effect of authentication that may occur between the client browser and the proxy (I've seen some scenarios where the webserver only checks the FIRST request and 'assumes' that following requests are the same user... Oops...). You need to get the mask correct for the oneconnect IP address matching too (The only time I really use it is for SSL and bypassing one of the ends that doesn't do HTTP keepalives). This might pose a problem if we are to use OneConnect. A school could have different restrictions for teachers and students, so if a teacher was to authenticate first then from what you're saying this could potentially mean that a student might just be allowed through using the same credentials as the teacher??? In order to answer those questions would require a lot more information... e.g. Do you do authentication? And by what method? H Yes we do authentication. The squid box does the authentication, but I'm not 100% sure how it all works as I don't really look after the squid boxes.

Hi All, Just wondering if we are able to use SSL persistence so that schools use the same node (proxy) for HTTPS traffic (port 443)? We've had problems in the past when schools do their banking and if they do not go through the original proxy that made the HTTPS connection to the bank then the session would not be valid if they then went through a different proxy for subsequent transactions. I've had a read of SSL persistence and it doesn't seem to do what I've described above. https://support.f5.com/kb/en-us/solutions/public/3000/200/sol3245.html "You can only use SSL persistence with nodes that are running SSL, where BIG-IP load balances only encrypted traffic. You cannot use SSL Persistence with any connections that are handled by an SSL proxy." The nodes are just proxy servers and are not running any SSL. So based on the literature above, is it correct to say that SSL persistence won't help with us make HTTPS connections sticky??? Thanks. Andy

Hi Andy, SSL session ID persistence definitely wouldn't work for HTTPS traffic tunneled over HTTP to a web proxy as the base connection is over HTTP. Persistence isn't really going to affect the server side connection re-use though. Aaron

You might be able to use cookie persistence though... I'm pretty sure the browser includes cookies in the CONNECT request... You would have to do something clever though to include cookies with every request... Is your authentication browser basic? Or forms based (Browser basic would be a lot easier, because you could then persist on the proxyauth headers). Or if the requests include XForwarded-For headers... You could persist on them. H

OneConnect and Proxy/Squid Load Balancing

31 Replies

mikand_61525
Nimbostratus
Jan 12, 2012
Note to self: When using "SSL Proxy" in your webbrowser it means that the request is sent in cleartext to the forward https-proxy.

It turned out that oneconnect (using /32 mask) seems to be working just fine but http profile can only be attached to the vserver for the forward http-proxy and not the forward https-proxy.

Perhaps any of you in here who previously have stumbled upon this behaviour and know a workaround other than setting http profile to none?

Because when set to none I will also miss AVR (statistics) and ability to use ASM :-(
nitass
Employee
Jan 13, 2012
without private key, i do not think we can use either asm or avr with https proxy since you know we are not able to see clear text traffic.
mikand_61525
Nimbostratus
Jan 14, 2012
I can use a private key because I do ssl-termination further out in the chain, but will that work since the http profile doesnt seem to allow CONNECT as method?

When I tested with the http profile enabled for VS_FORWARD-HTTPS the F5 will just send the client a FIN-ACK as soon as it receives the CONNECT request (the F5 doesnt even forward the traffic to the forward-proxy).

Can I somehow alter the http profile to allow CONNECT?
nitass
Employee
Jan 14, 2012
i am trying to setup in lab but i am a bit confused about your setting. would you mind posting the VS_FORWARD-HTTPS virtual and its pool configuration here?

and how did you test? what proxy setting did you set in browser?

mikand_61525

Nimbostratus

Jan 14, 2012

Sure, I hope the attached code is enough to reproduce this?

The setup is:

Physical address of the forward http(s)-proxy is 10.1.1.254 which listens to 3128 for http and 3129 for https (in this test-setup I just use one box, in true scenario there will more than one).

This is verified to work when you in your browser (firefox) sets the following settings:

Manual proxy configuration:

HTTP Proxy: 10.1.1.254:3128

SSL Proxy: 10.1.1.254:3129

Virtual address of the forward http(s)-proxy is 10.2.1.1 which also listens to 3128 for http and 3129 for https.

Which means that you need these settings in your browser to let F5 do its magic (both as loadbalancer but also as protocol inspector):

Manual proxy configuration:

HTTP Proxy: 10.2.1.1:3128

SSL Proxy: 10.2.1.1:3129

The VS_PROXY_HTTP uses http profile, http class, analytics, oneconnect and a small tcp-lan-optimized tweak and works like a charm.

The VS_PROXY_HTTPS doesnt so I (in the uploaded code) have disabled http profile which also means that I am forced to disable the http class AND analytics 😞 in order to make it work. If you enable the http profile you will notice that the F5 will just send FIN-ACK in return as soon as the client sends its "CONNECT https://www.example.com:443/".

As a sidenote I have also tried to disable oneconnect (even if its enabled in the uploaded code).

The configuration is pretty straight forward (sure I have tweaked the monitors but thats just to make it less aggressive because each ping etc generates log-entries in the forward-proxy).

The logical flow for the packets is more or less:

client -> F5 -> forward-http(s)-proxy -> application firewall -> external net

The application firewall is set to do SSL-termination so I could load the private key used for this in the F5 and use as server-ssl if needed, but then again - I believe the problem is in how the http profile functions (my best guess so far is that the http profile doesnt allow "CONNECT" as method) simply because the VS_PROXY_HTTPS works when I disable the http profile.

There is also a new setting (I think when you setup client/server-ssl) named "proxy ssl" which I wonder if it would help in my case?

Oh and the firmware used is v11.1.

 
ltm default-node-monitor {
    rule /Common/ICMP_PROXY 
}
ltm node /Common/PROXY1 {
    address 10.1.1.254
}
ltm pool /Common/POOL_PROXY_HTTP {
    load-balancing-mode fastest-node
    members {
        /Common/PROXY1:3128 {
            address 10.1.1.254
        }
    }
    monitor /Common/inband and /Common/TCP_PROXY 
    service-down-action reset
}
ltm pool /Common/POOL_PROXY_HTTPS {
    load-balancing-mode fastest-node
    members {
        /Common/PROXY1:3129 {
            address 10.1.1.254
        }
    }
    monitor /Common/inband and /Common/TCP_PROXY 
    service-down-action reset
}
ltm virtual /Common/VS_PROXY_HTTP {
    destination /Common/10.2.1.1:3128
    http-class {
        /Common/HTTPCLASS_PROXY
    }
    ip-protocol tcp
    mask 255.255.255.255
    persist {
        /Common/SOURCE_ADDR_PROXY {
            default yes
        }
    }
    pool /Common/POOL_PROXY_HTTP
    profiles {
        /Common/ANALYTICS_PROXY { }
        /Common/HTTP_PROXY { }
        /Common/ONECONNECT_PROXY { }
        /Common/TCP-LAN-OPTIMIZED_PROXY { }
    }
    vlans-disabled
}
ltm virtual /Common/VS_PROXY_HTTPS {
    destination /Common/10.2.1.1:3129
    ip-protocol tcp
    mask 255.255.255.255
    persist {
        /Common/SOURCE_ADDR_PROXY {
            default yes
        }
    }
    pool /Common/POOL_PROXY_HTTPS
    profiles {
        /Common/ONECONNECT_PROXY { }
        /Common/TCP-LAN-OPTIMIZED_PROXY { }
    }
    vlans-disabled
}
ltm virtual-address /Common/10.2.1.1 {
    address 10.2.1.1
    mask 255.255.255.255
    traffic-group /Common/traffic-group-1
}
ltm monitor icmp /Common/ICMP_PROXY {
    defaults-from /Common/icmp
    destination *
    interval 15
    time-until-up 0
    timeout 46
}
ltm monitor tcp /Common/TCP_PROXY {
    defaults-from /Common/tcp
    destination *:*
    interval 15
    time-until-up 0
    timeout 46
}
ltm persistence source-addr /Common/SOURCE_ADDR_PROXY {
    app-service none
    defaults-from /Common/source_addr
    timeout 3600
}
ltm profile analytics /Common/ANALYTICS_PROXY {
    captured-traffic-external-logging disabled
    captured-traffic-internal-logging enabled
    collect-geo enabled
    collect-http-throughput enabled
    collect-ip enabled
    collect-methods enabled
    collect-page-load-time enabled
    collect-response-codes enabled
    collect-server-latency enabled
    collect-url enabled
    collect-user-agent enabled
    collect-user-sessions enabled
    collected-stats-external-logging disabled
    collected-stats-internal-logging enabled
    defaults-from /Common/analytics
    description none
    notification-by-email disabled
    notification-by-snmp disabled
    notification-by-syslog disabled
    remote-server-ip any6
    remote-server-port 514
    remote-server-syslog-facility local0
    session-timeout 300
    session-timeout-minutes 5
    traffic-capture {
        capturing-for-ANALYTICS_PROXY {
            captured-protocols all
        }
    }
    trust-xff enabled
}
ltm profile http /Common/HTTP_PROXY {
    app-service none
    defaults-from /Common/http
    security enabled
}
ltm profile httpclass /Common/HTTPCLASS_PROXY {
    app-service none
    asm enabled
    defaults-from /Common/httpclass
}
ltm profile one-connect /Common/ONECONNECT_PROXY {
    app-service none
    defaults-from /Common/oneconnect
    max-age 3600
    source-mask 255.255.255.255
}
ltm profile tcp /Common/TCP-LAN-OPTIMIZED_PROXY {
    app-service none
    defaults-from /Common/tcp-lan-optimized
    proxy-buffer-high 280000
    proxy-buffer-low 277000
}

nitass
Employee
Jan 15, 2012
what proxy are you using? is it squid? may i also have squid configuration?

nitass

Employee

Jan 15, 2012

i am not much familiar with squid. wondering if there is any special when configuring https proxy i.e. port 3129. is it just another instance like port 3128?

[root@ve1023:Active] config  b virtual bar1 list
virtual bar1 {
   snat automap
   pool foo1
   destination 172.28.19.79:3128
   ip protocol 6
   profiles {
      http {}
      tcp {}
   }
}
[root@ve1023:Active] config  b pool foo1 list
pool foo1 {
   members 172.28.19.251:3128 {}
}
[root@ve1023:Active] config  b virtual bar2 list
virtual bar2 {
   snat automap
   pool foo2
   destination 172.28.19.79:3129
   ip protocol 6
   profiles {
      http {}
      tcp {}
   }
}
[root@ve1023:Active] config  b pool foo2 list
pool foo2 {
   members 172.28.19.251:3129 {}
}


 curl -Ik https://www.google.com/ -x 172.28.19.79:3129
HTTP/1.0 200 Connection established

HTTP/1.1 200 OK
Date: Sun, 15 Jan 2012 04:40:45 GMT
Expires: -1
Cache-Control: private, max-age=0
Content-Type: text/html; charset=ISO-8859-1
Set-Cookie: PREF=ID=7d5331ea4cb18cc1:FF=0:TM=1326602445:LM=1326602445:S=XqerRof5YDSF_HmF; expires=Tue, 14-Jan-2014 04:40:45 GMT; path=/; domain=.google.com
Set-Cookie: NID=55=RAt7S2S7r0ObTTPxyMjBDgD32anR8fjyt-4_syPbnTIVIZNXsDp05oB0IvLlm-7Crd7Djrmw5ZJdWyKV5ADooEWHwEj6yzJGDADudQfx8i5mU6PvRa7JVEzdSFjzR2Cs; expires=Mon, 16-Jul-2012 04:40:45 GMT; path=/; domain=.google.com; HttpOnly
P3P: CP="This is not a P3P policy! See http://www.google.com/support/accounts/bin/answer.py?hl=en&answer=151657 for more info."
Server: gws
X-XSS-Protection: 1; mode=block
X-Frame-Options: SAMEORIGIN
Transfer-Encoding: chunked


[root@ve1023:Active] config  ssldump -Aed -nni 0.0 port 3129
New TCP connection 1: 172.28.19.253(35339) <-> 172.28.19.79(3129)
1326602789.8656 (0.0030)  C>S
---------------------------------------------------------------
CONNECT www.google.com:443 HTTP/1.0
Host: www.google.com:443
User-Agent: curl/7.15.5 (i686-redhat-linux-gnu) libcurl/7.15.5 OpenSSL/0.9.8r zlib/1.2.3 libidn/0.6.5
Proxy-Connection: Keep-Alive

---------------------------------------------------------------

New TCP connection 2: 172.28.19.80(35339) <-> 172.28.19.251(3129)
1326602789.8667 (0.0010)  C>S
---------------------------------------------------------------
CONNECT www.google.com:443 HTTP/1.0
Host: www.google.com:443
User-Agent: curl/7.15.5 (i686-redhat-linux-gnu) libcurl/7.15.5 OpenSSL/0.9.8r zlib/1.2.3 libidn/0.6.5
Proxy-Connection: Keep-Alive

---------------------------------------------------------------

mikand_61525
Nimbostratus
Jan 15, 2012
No its not squid and which portnumber one use doesnt really matter. You can use 1234 in your tests if you like.

And in this case the F5 doesnt even forward the traffic to the proxyservers when I enable http profile for the VS_PROXY_HTTPS so the "error" is in the F5 and not somewhere else (verified by tcpdump on the F5 unit for the interface connected to the proxyserver).

But as soon as I disable the http profile (and also disables http class and analytics since they depend on the http profile) then I can use VS_PROXY_HTTPS.

But I can try to redo the tests on monday/tuesday and get back with the failing config (unless someone else got some tips to test at the same time?).
Spidey_29396
Nimbostratus
Feb 21, 2012
Hi nitass,

We are configuring F5 to load balance squid web cache proxy:

This is the flow:

Client >> F5(rewrite) >>F5 forward to cache proxy servers>>Cache proxy servers >> F5(transparent) >> Client

Inbound and outbound traffic falls on the same VLAN. Using same interface

INBOUND: From internet to firewall to F5

OUTBOUND: F5 to Cache servers

VS is configured for the 2 cache servers

Used iRule to rewrite URL

Objective:

To be able to rewrite the URL and then gets passed to the cache servers after the rewrite.

Maintain the session

So traffic gets cached.

Client initiates HTTP request with URL: www.google.com.example.com.ph

With iRule,example.com.ph gets truncated, then returns back www.google.com to the client browser.

This is working, and F5 rewrites it

However, upon rewriting F5 must forward it to the cache servers.

Problem:

traffic is not getting a hit on the cache servers.

From the iRule, it seems that once URL is rewritten traffic gets redirected and doesn’t go to cache.

virtual LB-Voyager {

snat automap

pool LB_Voyager-MIB_3128

destination 10.128.142.60:http

ip protocol tcp

rules LB_Voyager6

persist beta_mysandbox_cookie_insert

profiles {

http_beta_mysandbox {}

tcp {}

}

}

}

pool LB_Voyager-MIB_3128 {

monitor all gateway_icmp and tcp_3128

members {

10.128.142.58:squid {}

10.128.142.61:squid {}

}

}

rule LB_Voyager6 {

when HTTP_REQUEST {

set host [string tolower [HTTP::host]]

set newhost [string map {".example.com.ph" ""} $host]

if {$host ne $newhost} {

HTTP::redirect "http://$newhost[HTTP::uri]"

}

}

but we are not hitting the servers.
- Mahmoud_ElSoury
  Nimbostratus
  Jul 14, 2015
  Hi Spidey, Was the problem resolved, I have the same problem now.
- Spidey_29396
  Nimbostratus
  Jul 15, 2015
  Hi Mahmoud ElSoury, Unfortunate client didn't push thru with the project. Thanks! Ferdz

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