I had to replace my original Samsung Galaxy S4 fairly recently (having accidentally generated a small field and frying a few components... long story).
The new phone is very slow to connect when on wifi, and has been since I got it (only just got around to starting to look into it properly though).
Having run packet captures, it's not the connection itself that's slow, but the phone seems to wait around 5 seconds before the SYN even hits the wire. After that the connection is fine. Not seeing any signs of packet loss.
Phone isn't rooted (previous one was), and I've previously had both "No Root Firewall" and "OpenVPN Connect" installed on it.
The issue seems to affect all connections rather than just a specific browser or something like that.
Seems to consistently be 5 seconds, suggesting it's waiting for something to time out before it actually starts trying to establish the connection. Where a site calls resources from multiple domains/servers (by, for example, using a CDN), that can easily translate into a 30 second wait for the page to load fully.
Raising this issue to track troubleshooting, as there don't seem to be any resources on Google to help narrow this issue down - most are concerned with the more commonly known issues with wifi on the S4. I've ruled those out:
- Keep Wi-Fi on during sleep is enabled
- WIFI Power Save Mode is off
Another S4 on the network (running a slightly older version of Android) doesn't have this issue. Doesn't mean it definitely isn't something on the network, but as far as I can see, the network is running fine. The phone does seem to behave on 4G though.