Hopefully this threads answers all of your questions regarding this glitch, but if not, then please post a reply and we'll try to explain further.
Brief History/Explanation of the Glitch I started playing GTA IV multiplayer more frequently after patch 1.03 came out (the one that gave us trophies), and since then I had experienced the Bomb Da Base II drop glitch several times. Fortunately, though, there's a way around it, but allow me explain the issue first.
I had e-mailed back and forth with Take-Two and they reported that the reason for the drops is because of a port misconfiguration with a player's PS3 online setup. This being the case, you will only experience the drop glitch when all three of the following conditions are met:
The mission has started and is running
Someone who is playing has their ports misconfigured
Someone new joins in and/or someone drops out before arriving on the ship
It doesn't matter who joins in or who drops out. As long as one player has their ports misconfigured and a new player joins or one drops out, everyone in the session will get dropped back to singleplayer as soon as you try to approach the ship either by land, water, or air.
How can you avoid the glitch?The easiest way to avoid this glitch is to play BDBII with people whom you trust and who won't drop out before arriving on the ship. If you play with random people joining in, then you'll risk the possibility of someone new randomly popping in or someone dropping out or getting kicked out, especially if they're being monkeys and are throwing grenades at the SUV's that you start with; trust me, I've placed my fair share of votes against said monkeys. =p
The best setup is to create a custom match, set private slots to Max, and invite your buds to help you do the mission. I've played that mission dozens of times with people who've asked for help with getting the Fly the Co-op trophy and we've never gotten dropped from the mission.
Does this glitch happen anywhere else? So far, BDBII is the only mission that I know of that has this issue, but then again, it's the only one that I've played extensively with random people and it's the only one that has kicked me out if someone new joins or some gets dropped.
Rockstar owes us a patch that fixes several issues, but seeing as how their hands are tied at the moment with everything else that they're doing, we have to resort to going through workarounds to get what we want.
Hopefully that helped all of you GTA IV online multiplayer fans,
- Churro
P.S. For those who are curious as to what ports need to be opened between the internet and your PS3, the Take-two tech support agent who helped me stated the following:
Please open the below port numbers in any router that you may be using.
PS3 uses ports 6672 (UDP), 8001 (TCP), 28900 (UDP), 27900 (TCP).
For access to Playstation Network the following ports are used:
TCP:
80 (HTTP)
8080 (HTTP)
443 (HTTPS)
5223 (JABBER)
3478, 3479, 3480
UDP:
3478, 3479
If you are unsure on how to open port number in your router, please contact your router manufacturer.
P.P.S. A great site that has walkthrough guides on properly configuring your modem/router is
www.portforward.com - there's even a section dedicated exclusively to configuring devices for the PS3.