Anti-crawler cracking combat: in-depth analysis of User-Agent and IP rotation strategy

When Reptiles Meet Brass Tacks: The Laws of Survival for Anti-Reptiles

Brothers engaged in data collection should have experienced this kind of crazy moments: yesterday was running well crawler, this morning suddenly 404. Anti-crawler mechanism is like a gatekeeper, a little inattention will stop you at the door. At this time, do not rush to smash the keyboard, master the two keys -User-Agent Rotationrespond in singingIP camouflage, can make your crawlers as invisible as a chameleon.

Seventy-two variations of user agents

Many websites will recognize bots by User-Agent. We can prepare an arsenal of dozens of UA strings for different browser versions. Here's a trick for you: don't use an off-the-shelf library on the web, write your own randomizer in Python:

import random

def generate_ua(): chrome_versions = [f'Chrome/1{random.randint(10,25)}.
    chrome_versions = [f'Chrome/1{random.randint(10,25)}.0.{random.randint(1000,9999)}. {random.randint(1,200)}'
                      for _ in range(20)]
    return f'Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) {random.choice(chrome_versions)} Safari/537.36'

Note that there is a bit of random number range overlap to make the generated version number look more realistic. Don't underestimate this detail, as many anti-crawler systems focus on version number sequences that are "too perfect".

Guerrilla tactics with IP rotation

A UA disguise alone is like a change of clothes without a face; the IP address is the real ID. Here's a misconception to avoid:Don't believe in free agents.! Those IPs have long been blacklisted 800 times by major websites. I've used ipipgo's Dynamic Residential Proxy before, and his IP pool is big enough to automatically change IPs with each request, like installing a revolving door for crawlers.

In practice, it is recommended to useIP+UA ComboIf you want to change these two parameters at the same time for each request, you have to do it in a round-robin queue. Here's a tip: make the IP pool and the UA pool into two separate queues, and call them separately in a circular queue, which avoids patterned rotations being recognized.

Life and Death: Controlling the Frequency of IP Switching

IP switching is not the faster the better, according to the strength of the defense of the target site. Here is a reference table for you:

In particular, ipipgo's static residential agent is suitable for scenarios that require long-term session maintenance. Previously, there is a price monitoring project, with his static agent continuously staring at an e-commerce platform for 72 hours, froze without triggering the verification mechanism.

Pothole Facts: The Cars That Tumbled All Those Years Ago

1. time zone trapI've used a US IP to access a website, and the UA showed Chinese language, so I got caught out on the spot. Later, I added the matching logic between IP location and UA language in the code, and only then I was able to get away with it.

2. Cookie Chain: There's a site that puts a stake in the cookie, so that successive requests must be made with a specific logo. That's when you have to use ipipgo'ssticky sessionfeature that allows the same IP to maintain a long enough session.

Practical QA First Aid Kit

Q: How come I still get banned even though I changed my IP?
A: Check whether the request header carries client-side fingerprints (e.g., Canvas fingerprints), and it is recommended to disable WebGL functionality in the crawler.

Q: How to choose between dynamic IP and static IP?
A: Dynamic for HF collection, static for long term tasks. ipipgo's Enterprise package can be mixed, it is recommended to apply for a trial set to test first!

Q: How do I break the CAPTCHA when I encounter it?
A: Appropriately reduce the frequency of requests, with ipipgo's accurate city positioning function, simulating the geographic distribution characteristics of real users

Lastly, the anti-climbing confrontation is essentially a cost game. Instead of spending a lot of time hard just, it is better to choose a reliable proxy service. Like ipipgo's dynamic residential enterprise version, comes with intelligent switching rule base, than their own tossing a lot of worry. Remember, our goal is to get the data, not when the hacker attack and defense experts.