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Proxy PAC file is not working properly on I.E 11

I am hosting proxy.pac on my web gateway (Virtual) appliance . It bypasses the internal IPs and local domain name as expected in Chrome but not in I.E 11.Error which i get is "The host is not resolvable"  . I don't expect  the bypassed subnets to hit proxy and get this error.Allow/block is working as required for external domains as required. Is anyone aware of similar scenario. what could be the work around .Below is my Proxy PAC file

function FindProxyForURL(url, host) {

// If the hostname matches, send direct.

    if (dnsDomainIs(host, "") ||

        shExpMatch(host, "(*|"))

        return "DIRECT";

// If the requested website is hosted within the internal network, send direct.

    if (isPlainHostName(host) ||

        shExpMatch(host, "*.local") ||

        isInNet(dnsResolve(host), "10.x.x.x", ""))

        return "DIRECT";

// DEFAULT RULE: All other traffic, use below proxies.

    return "PROXY 10.100.x.x:9090; DIRECT";


4 Replies
Reliable Contributor Hayton
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Message 2 of 5

Re: Proxy PAC file is not working properly on I.E 11

Moved from Support Forums to Business > Email and Web Security > Web Gateway

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Message 3 of 5

Re: Proxy PAC file is not working properly on I.E 11

Can you show how did you add proxy pac to IE ?

Re: Proxy PAC file is not working properly on I.E 11

Is your client pointing directly to the MWG file server port or to do have a rule to handle the PAC file and redirect to internal next hop?

Also, based on your PAC file, a DNS resolution will be done locally on the client (to determine the result of the PAC file execution).

So make sure DNS is working OK.

Re: Proxy PAC file is not working properly on I.E 11

Keep in mind that dnsDomainIs is explicit.

Is your issue with matching in the first or second ruleset? I am assuming here the issue is the rule:   isInNet(dnsResolve(host), "10.x.x.x", ""))

Chrome is usually less forgiving than IE in terms of the PAC file. Are all sites broken or only those specific to the above rule? How is IE configured on the connection settings screen?

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