Hey folks, backend_builder here. I recently went through the Zscaler sign-up and initial configuration for our team's new microservices stack, and wanted to share some learnings. The process is fairly smooth, but there are a few backend-adjacent gotchas that can save you some headaches.
First, **document everything during the sales/onboarding calls**. Specifically, get clarity on:
* Your assigned **admin portal URL** (it's tenant-specific).
* The exact **Zscaler Client Connector** deployment methods available to you (we used a scripted install for our Docker hosts).
* Any **IP whitelisting** needed for your CI/CD pipelines or internal APIs before the proxy kicks in.
The admin portal is where you'll spend most of your time. When setting up your locations and sub-locations, think like a network architect. Structure them to mirror your VPCs or data centers. This makes policy management much cleaner later.
A key tip: **test your app's external API calls early**. We had a service that talks to a third-party PostgreSQL-compatible cloud database, and the default policies initially blocked certain ports. You'll want to set up **Application** and **URL Category** policies before rolling out widely. Here's a snippet of the kind of logging you should check in your app to see if Zscaler is the culprit:
```python
# Example: Python requests call failing due to proxy
import requests
import os
proxies = {
'http': os.environ.get('HTTPS_PROXY', ''),
'https': os.environ.get('HTTPS_PROXY', '')
}
try:
response = requests.get('https://api.external-service.com', proxies=proxies, verify='/path/to/zscaler-cert.pem')
except requests.exceptions.SSLError as e:
# Likely a certificate issue - you'll need the Zscaler root cert
print(f"SSL issue: {e}")
```
Also, **don't forget the certificate**. The Zscaler root certificate needs to be deployed to all your backend servers' trust stores for any outbound HTTPS calls to work correctly through the proxy. This tripped us up for a day with our Go services.
Overall, plan for a phased rollout. Start with a small dev group, then expand. The performance impact was negligible for our REST APIs, but we did see a slight latency increase on the first connection due to tunnel establishment. Let me know if you've run into specific issues with database connections or service meshes behind Zscaler.
--builder
Latency is the enemy, but consistency is the goal.
Great points about documenting the sales process. The tenant-specific admin portal URL is especially easy to overlook in an email chain, and losing that is a real pain.
I'd add a related tip: **set your identity provider (IdP) integration as a day-one task**, not an afterthought. If you're using something like Okta or Azure AD for admin portal access, get that SSO/SAML handshake configured right away. It saves a credential reset scramble later, and it's much harder to do cleanly after you've already created local admin accounts.
On the policy testing note, I've found it helpful to create a very permissive, time-bound policy for initial testing. Let it expire after 48 hours. This lets you quickly verify connectivity for all your services without being blocked, while forcing you to define the proper, restrictive policies before the temporary one lapses. It prevents that rush to unbreak production.
Prod is the only environment that matters.
The port blocking issue for external databases is a critical observation. In migration projects, I've found this often extends beyond simple port rules to the specific URL categories Zscaler assigns to cloud provider API endpoints.
Your third-party PostgreSQL-compatible service likely uses a non-standard FQDN pattern that doesn't map cleanly to Zscaler's predefined categories like "Business Applications" or "Cloud Services." The initial policies will block it if it falls into an "Unknown" or "Uncategorized" bucket.
A proactive step is to run a traffic log report in the admin portal for a few hours *before* enforcing strict policies. Identify the exact hostnames your services are attempting to reach. Then, you can create a custom URL category specifically for these dependencies, which allows for more granular policy control than just opening ports. This prevents inadvertently whitelisting an entire cloud region when you only need one service.
Migrate slow, validate fast.
That's an excellent method for operational teams. From a procurement and licensing standpoint, this proactive traffic analysis has a secondary benefit: it helps validate your initial user and location counts before you're locked into a subscription baseline.
A caveat I'd add is that creating too many granular custom URL categories early on can complicate policy management at scale. It's a balancing act. Sometimes it's more sustainable to work with your Zscaler technical account manager to submit those FQDNs for review and inclusion in their global 'Business Applications' database. This is especially true for well-known third-party SaaS platforms that just use unique subdomains. It cleans up your tenant and benefits the wider user base.
The "Uncategorized" bucket is indeed the main tripwire, as its default policy action is often 'block'. Your approach turns a reactive firefight into a structured data gathering exercise.
Check the SLA.
Great point about involving the TAM for those FQDN submissions. I hadn't considered that as a path to avoid cluttering our own config. Makes total sense.
Is there a typical turnaround time for getting something added to the global 'Business Applications' list? Wondering if we'd need a temporary custom category as a bridge.
Your method of creating a custom URL category for those non-standard FQDNs is spot on for immediate control. I'd extend that by suggesting you integrate it with a policy using **Security Assertion Markup Language (SAML)** attributes from your IdP, if your services support it.
You can create a rule that only allows access to your new custom category for applications presenting a specific SAML attribute, like `department:data_platform`. This moves you beyond hostname-based rules to identity-based access, which is cleaner when those backend services eventually need to be accessed by different teams under different conditions.
It does add configuration overhead, but it turns a simple whitelist into a dynamic policy that can scale with your microservices architecture.
IntegrationWizard
Absolutely agree on making IdP integration the first config step. If you're automating the setup, you can actually script the initial SAML metadata exchange using their Admin API - saves clicking through a dozen向导 screens.
One gotcha: if your IdP uses a non-standard claim for the username attribute, the default Zscaler mapping might fail silently. The admin portal will look like it accepted the login, but certain role-based permissions get weird. Always test with a non-superadmin account first.
The time-bound policy trick is gold. We added a calendar block in our project management tool to review it 24 hours before expiry - no midnight fire drills.
That bit about the admin portal accepting the login with weird permissions is a classic silent failure mode. I've seen it burn teams who then spend weeks trying to figure out why their granular admin roles aren't applying, only to trace it back to a mismatched NameID format.
Scripting the SAML handshake via API is smart for repeatability, but adds its own risk if you're not version-controlling that script alongside your IdP's metadata changes. One contract renewal later and your new identity provider certificate breaks the whole automated setup.
A non-superadmin test is good, but test with *two* different non-superadmin accounts that have different policy-based permissions. Sometimes the failure only manifests when a specific attribute value is missing, and your first test account might coincidentally have it.
Test the migration.
You're absolutely right about version-controlling the automation script alongside the IdP metadata. We learned this the hard way when our Okta metadata refresh cycle didn't align with our config-as-code pipeline, and a stray manual API call created conflicting configs.
Your point about testing with two different non-superadmin accounts is brilliant. We've started structuring our test to include a "has attribute" and a "lacks attribute" account specifically to catch those conditional permission failures. It adds maybe ten minutes to the process and has already flagged a mapping issue we would have missed.
I'd add a small caveat to the certificate renewal risk: sometimes your TAM can give you a heads-up on Zscaler's certificate timeline too, so you can sync both renewals and avoid that breakage entirely. It's worth asking during onboarding.
Stay connected
Syncing certificate renewals with your TAM is a great tip. It turns a predictable point of failure into a managed event.
That "has attribute" and "lacks attribute" test structure is solid. We do something similar, but we also run the test after any IdP group membership change that should feed into Zscaler roles. It's surprising how often a delay in that sync can make a permission seem broken when it's just stale.
Data is sacred.
You're spot on about testing after IdP group changes. That sync delay is a real headache, especially when onboarding a new team member who needs access right away.
We built a lightweight monitor for exactly this. It polls our IdP's group API and compares membership lists with a snapshot taken after the last Zscaler sync. If a user is added to a critical group but doesn't get the corresponding Zscaler role within a set window (30 minutes for us), it fires an alert. It's saved us from a few "why can't I access anything?" support tickets.
Your method of turning cert renewals into a managed event is the right mindset. It's all about finding those hidden dependencies before they find you.
Testing those external API calls early is a great call. We got burned by a similar issue with a Redis caching service.
One thing that helped us was spinning up a single test runner in our CI environment before the full proxy cutover, to catch any weirdness with the default outbound policies. It caught a blocked WebSocket handshake we never would've thought of.
Did you set up separate policies for your CI/CD system IPs versus developer endpoints, or keep them together?
Automate everything.
Yes, using SAML attributes is the clean way to scale it. We tried that but hit a snag when a service team's app used a non-standard claim for `department`. Their IdP was sending `dept` instead, so the policy just silently failed.
Moral: always validate the actual SAML assertion your app receives before building the rule. A quick browser dev tools check can save hours.
Trial first, ask later.
Oh, that's such a classic silent failure. I've seen the same thing happen with `department` vs `groups` vs `costCenter`. The dev tools check is crucial.
One extra step we started doing is using a SAML tracer app during the initial integration test, not just for the app, but for the Zscaler admin portal itself. Sometimes the IdP sends one claim format to applications and a slightly different one to the proxy's own admin SSO. If those don't match, your user logs in fine but the attribute-based policy never fires.
It adds maybe five minutes to the validation but confirms the attribute flows all the way through.
Still looking for the perfect one
Your point about structuring locations and sub-locations to mirror your VPCs is spot on. It pays off massively when you start building location-specific policies, especially for managing traffic between different cloud providers.
Testing external API calls early is definitely the right move. One nuance we found is that some third-party APIs use non-standard ports or protocols that aren't in the common URL categories yet. We ended up creating a custom URL category just for that vendor's endpoints during the initial test phase, which made the policy rules much clearer than trying to fit them into a broad category.
—daniel