Squid Proxy "Bypass Proxy for These Destination IPs" Not Working?? Transparent HTTP Proxy Mode + HTTPS/SSL Interception

[michmoor]

@periko WPAD is for whn you are running an explict proxy right? Otherwise in a Transparent set up what would be the requirement?

[dkzsys]

@periko said in Squid Proxy "Bypass Proxy for These Destination IPs" Not Working?? Transparent HTTP Proxy Mode + HTTPS/SSL Interception:

@dkzsys I see u have add a lot of custom settings, squid will filter +/- 90% of the traffic.
Now, this apple things maybe is inside that 10% that will reject to work behind a proxy.

What version of pfsense u have?

My recommendation:

Resolve DNS IPv4 First doesn't work, is a obsolete is u are running pfsense 2.6+.
Your alias in the bypass finish them with ';'
Try splice all.
Remove all that custom stuff.
Select all in the "Remote Cert Checks and Certificate Adapt".
Enable WPAD in your interface where u want to run squid.

I don't have apple stuff that I can test, I will check evernote.

Now, what is the problem with 'Evernote'?, I can try that app.

Regards!!!

Thanks for chipping in, Pedro @periko

I am running pfSense Plus 23.05.1-RELEASE (amd64) (built on Wed Jun 28 03:57:27 UTC 2023 FreeBSD 14.0-CURRENT).

Will try out your recommendations.

Re a couple of your points:

• "Try splice all." - do you mean, in addition to source ip address bypass, splice them all in squid config as well? Ignore this, figured out that you were referring to "SSL/MITM Mode" setting.

• "Remove all that custom stuff." They were automatically added after installing suiqdGuard I think. I'll remove the config and uninstall squidGuard for now.

Re Evernote, I had to whitelist "www.evernote.com", otherwise, the app is having sync issue with the server. On macOS app, it's a grey pop-up error box on the note page when I tried to update the note. For a failure scenario testing, it's easier to use this URL "https://www.tradingview.com/markets", as it worked on Mike's, and failed on mine and Jonathan's.

[periko]

@michmoor It wont' affect at the end the client will need to reach the proxy.

The only difference is that transparent pfsense will forward the traffic to the proxy in no none we need to allow the client reach the proxy, resume both options the client will need to reach the proxy.

Regards!!!

[periko]

@dkzsys I need to get a apple to test, just curiosity, in a windows box evernote do the same thing?

[dkzsys]

@periko said in Squid Proxy "Bypass Proxy for These Destination IPs" Not Working?? Transparent HTTP Proxy Mode + HTTPS/SSL Interception:

@dkzsys I need to get a apple to test, just curiosity, in a windows box evernote do the same thing?

Let me try it on a windows VM and let you know. If you are interested in the broken SSL session, you can use "https://www.tradingview.com/markets" to test.

Enable WPAD in your interface where u want to run squid.

A question for your point above, do you mean enabling WPAD on the interface setting on pefsense (if so, do you mind letting me how to do it?), or enabling WPAD or PAD on the client machine (either os system setting, or browser setting)?

[dkzsys]

@periko said in Squid Proxy "Bypass Proxy for These Destination IPs" Not Working?? Transparent HTTP Proxy Mode + HTTPS/SSL Interception:

@dkzsys I see u have add a lot of custom settings, squid will filter +/- 90% of the traffic.
Now, this apple things maybe is inside that 10% that will reject to work behind a proxy.

What version of pfsense u have?

My recommendation:

Resolve DNS IPv4 First doesn't work, is a obsolete is u are running pfsense 2.6+.
Your alias in the bypass finish them with ';'
Try splice all.
Remove all that custom stuff.
Select all in the "Remote Cert Checks and Certificate Adapt".
Enable WPAD in your interface where u want to run squid.

I don't have apple stuff that I can test, I will check evernote.

Now, what is the problem with 'Evernote'?, I can try that app.

Regards!!!

I have tried a few different config combinations, and the "Splice All" does most of the trick!

Some observations with "Splice All":

• "Remote Cert Checks" with only "Do not verify remote certificate"; and "Certificate Adapt" - none
  microsoft domains are mainly 409; but apple icloud gateway is getting 500.

1695347891.621      0 10.0.1.11 NONE_NONE/409 4012 CONNECT outlook.office365.com:443 - HIER_NONE/- text/html
1695347891.621      0 10.0.1.11 NONE_NONE/000 0 - error:transaction-end-before-headers - HIER_NONE/- -

1695347967.351     29 10.0.1.11 TCP_TUNNEL/500 7 CONNECT gateway.icloud.com:443 - ORIGINAL_DST/17.248.219.1 -

• After enabling all in "Remote Cert Checks" and "Certificate Adapt"
  Both microsoft domains and icloud gateway are getting 409.

1695348201.835      0 10.0.1.11 NONE_NONE/409 4003 CONNECT gateway.icloud.com:443 - HIER_NONE/- text/html
1695348201.835      0 10.0.1.11 NONE_NONE/000 0 - error:transaction-end-before-headers - HIER_NONE/- -

It would be easier for me to fix up all the 409s after leaving it running for a bit.

I've checked squid access log and it has sufficient info for my audit purpose.

Thank you for helping out, @periko @michmoor @JonathanLee! It fixed most of my issues for my particular use case with this less intrusive implementation. For Jonathan's use case of content filtering it would still need that extra work for whitelisting.

P.S. @periko no more evernote sync issue either after Splice All!

[JonathanLee]

@dkzsys
Check this out for WPAD

https://docs.netgate.com/pfsense/en/latest/recipes/http-client-proxy-wpad.html

It's a really good how to overview of WPAD. I have mine set up this way with an addition of DHCP options to automatically send the proxy and DNS information when IP addresses are distributed.

DHCP option 252 and 42

"A WPAD host may be supplied via DHCP numbered option 252 (string value containing the entire URL to the WPAD file) or DNS, which is easy to do with the built-in DNS forwarder" (Netgate docs).

Normally you would use standard ports again my GUI uses port 8080 and it works good for the XBOX One

[dkzsys]

@JonathanLee said in Squid Proxy "Bypass Proxy for These Destination IPs" Not Working?? Transparent HTTP Proxy Mode + HTTPS/SSL Interception:

@dkzsys
Check this out for WPAD

https://docs.netgate.com/pfsense/en/latest/recipes/http-client-proxy-wpad.html

It's a really good how to overview of WPAD. I have mine set up this way with an addition of DHCP options to automatically send the proxy and DNS information when IP addresses are distributed.

Thanks for the illustration as always @JonathanLee ! Yes - I went through the same page as well:)

For me, the next is to evaluate switching back to AdGuard Home for DNS on RaspberryPi, or use SquidGuard with pfSense DNS. Since I've blocked DNS (53, DoH, DoT) to WAN, and NATing locally, AdGuard would have a similar effect of SquidGuard in terms of service/domain blocking. (and neither approach will prevent kids bypassing with VPN). And at this stage, I don't need time-of-day control. So my criteria would be relatively simple:

• #1: no impact to Squid transparent proxy implementation (re earlier discussion in this thread)
• Ease of adding/removing domains
• Ease and effectiveness of rule toggles.

[JonathanLee]

@michmoor WPAD auto configures devices to use the proxy. It's for laptops that move from the office and back to home. It's so you an admin never need to set the poxy settings. When a known device jumps on your network the device already knows to use the proxy, versus having to configure it on the device each and every time you change from a lan at the office to your lan at home. It's explicitly for proxy use. It just does it automagically.

[dkzsys]

After a few days of testing with Transparent proxy + SSL Interception (Splice All), a couple of observations:

1. For the whitelisted source IP by FQDN (e.g. microsoft, Apple icloud etc), the result is intermittent - sometimes 200 and others 409... I have updated the "Aliases Hostnames Resolve Interval" to 60 sec. but still not resolved. Some input for resolution will be appreciated.

2. FW Blocking to WAN is no longer 100% effective, to the FQDNs on and off the source bypass list. For example, blocked clients can still search on google.com, play chess on chess.com, etc. See screenshot for the fw block rule below. I will have to reset fw states to block all outgoing traffic to WAN from those clients. @periko - can I get your input on this pls - any other options to effectively block client to WAN without fw state reset?

[JonathanLee]

@dkzsys if you use Squid or Squidguard you can utilize regular expressions.

Some examples from my always splice file:

^((alt[0-9]-mtalk.)|(mtalk.)|(mtalk-(staging|dev).))google.com

^(((clients)[0-9])|accounts).google.(com|us)

^.*(outlook.)(office365|office).com

^(disney.(content|connections)).edge.bamgrid.com

Test and create them with a regular expressions tester online if needed.

[dkzsys]

@JonathanLee my understanding is that for the regex domain to work, squid will need to be set to explicit mode, or transparent mode with peek and splice config; and it doesn't work for transparent mode with Splice All. Happy to be corrected.

[JonathanLee]

@dkzsys it should work if the domains are using .something else in it. Yes that is mostly used with SSL intercept

[dkzsys]

@dkzsys said in Squid Proxy "Bypass Proxy for These Destination IPs" Not Working?? Transparent HTTP Proxy Mode + HTTPS/SSL Interception:

2. FW Blocking to WAN is no longer 100% effective, to the FQDNs on and off the source bypass list. For example, blocked clients can still search on google.com, play chess on chess.com, etc. See screenshot for the fw block rule below. I will have to reset fw states to block all outgoing traffic to WAN from those clients. @periko - can I get your input on this pls - any other options to effectively block client to WAN without fw state reset?

I just found out that I can use "pfctl -k" to reset fw sessions for specific client IPs via terminal. Since I am using CLI to toggle the blocking rules, it actually worked out well for me as a workaround - simply adding the extra command in the block rule CLI snippet.

[dkzsys]

@dkzsys said in Squid Proxy "Bypass Proxy for These Destination IPs" Not Working?? Transparent HTTP Proxy Mode + HTTPS/SSL Interception:

I just found out that I can use "pfctl -k" to reset fw sessions for specific client IPs via terminal. Since I am using CLI to toggle the blocking rules, it actually worked out well for me as a workaround - simply adding the extra command in the block rule CLI snippet.

Unfortunately killing the state for the client still doesn't block their traffic to WAN with the block rule enabled... Looking for an alternative workaround.

[JonathanLee]

@dkzsys try this

client_persistent_connections on
client_persistent_connections off

"Squid uses persistent connections (when allowed). You can use
this option to disable persistent connections with clients."

http://www.squid-cache.org/Doc/config/client_persistent_connections/