[Galaxy Ace S5830i Android Development] Finn10111:
Im also also using latest RC3 on my 5839i and I don't have a working mobile data connection. But in my case it seems to be a DNS problem. Pinging IP or calling something like http://81.169.159.20 works. Also a manual nslookup works:

# nslookup finnchristiansen.de 208.67.222.222
Server: 208.67.222.222
Address 1: 208.67.222.222

Name: finnchristiansen.de
Address 1: 81.169.159.20
# cat /etc/resolv.conf
nameserver 8.8.8.8
nameserver 8.8.4.4
# nslookup finnchristiansen.de
Server: 0.0.0.0
Address 1: 0.0.0.0

nslookup: can't resolve 'finnchristiansen.de'

# ping finnchristiansen.de
ping: unknown host finnchristiansen.de
# ping 81.169.159.20
PING 81.169.159.20 (81.169.159.20) 56(84) bytes of data.
64 bytes from 81.169.159.20: icmp_seq=1 ttl=48 time=544 ms
64 bytes from 81.169.159.20: icmp_seq=2 ttl=48 time=325 ms
^C
--- 81.169.159.20 ping statistics ---
3 packets transmitted, 2 received, 33% packet loss, time 1999ms
rtt min/avg/max/mdev = 325.348/435.164/544.981/109.818 ms

EDIT:

I found something while I was browsing the source code and looked at the latest fix:

# getprop net.rmnet0.dns1
10.74.210.210
# setprop
usage: setprop <key> <value>
# setprop net.rmnet0.dns1=208.67.222.222
usage: setprop <key> <value>
# setprop net.rmnet0.dns1 208.67.222.222
# setprop net.rmnet0.dns2 208.67.220.220
# ping google.de
ping: unknown host google.de
# setprop net.dns2 208.67.220.220
# setprop net.dns1 208.67.222.222
# ping google.de
PING google.de (173.194.113.24) 56(84) bytes of data.
64 bytes from fra02s19-in-f24.1e100.net (173.194.113.24): icmp_seq=1 ttl=48 time=956 ms
64 bytes from fra02s19-in-f24.1e100.net (173.194.113.24): icmp_seq=2 ttl=48 time=1076 ms
^C
--- google.de ping statistics ---
3 packets transmitted, 2 received, 33% packet loss, time 2998ms
rtt min/avg/max/mdev = 956.543/1016.479/1076.415/59.936 ms, pipe 2
# ip addr
1: lo: <LOOPBACK,UP,LOWER_UP> mtu 16436 qdisc noqueue state UNKNOWN
link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
inet 127.0.0.1/8 scope host lo
inet6 ::1/128 scope host
valid_lft forever preferred_lft forever
2: usb0: <BROADCAST,MULTICAST> mtu 1500 qdisc noop state DOWN qlen 1000
link/ether 22:33:44:55:66:77 brd ff:ff:ff:ff:ff:ff
3: rmnet0: <NOARP,UP,LOWER_UP8000> mtu 1400 qdisc pfifo_fast state UNKNOWN qlen 250
link/generic
inet 10.153.193.242/24 scope global rmnet0
4: rmnet1: <NOARP8000> mtu 1400 qdisc noop state DOWN qlen 250
link/generic
5: rmnet2: <NOARP8000> mtu 1400 qdisc noop state DOWN qlen 250
link/generic
6: rmnet3: <NOARP8000> mtu 1400 qdisc noop state DOWN qlen 250
link/generic
7: rmnet4: <NOARP8000> mtu 1400 qdisc noop state DOWN qlen 250
link/generic
8: rmnet5: <NOARP8000> mtu 1400 qdisc noop state DOWN qlen 250
link/generic
9: rmnet6: <NOARP8000> mtu 1400 qdisc noop state DOWN qlen 250
link/generic
10: rmnet7: <NOARP8000> mtu 1400 qdisc noop state DOWN qlen 250
link/generic
11: rmnet8: <NOARP8000> mtu 1400 qdisc noop state DOWN qlen 250
link/generic
12: rmnet9: <NOARP8000> mtu 1400 qdisc noop state DOWN qlen 250
link/generic
13: sit0: <NOARP,UP,LOWER_UP> mtu 1480 qdisc noqueue state UNKNOWN
link/sit 0.0.0.0 brd 0.0.0.0
inet6 ::10.153.193.242/96 scope global
valid_lft forever preferred_lft forever
inet6 ::127.0.0.1/96 scope host
valid_lft forever preferred_lft forever

I changed the dns in the system props and mobile connection and dns resolution is working as expected. Is it normal that android doesn't use the dns server from the /etc/resolv.conf?

EDIT2:

To fix this temporary put this in /sd-ext/userinit.sh

#!/sbin/sh
setprop net.dns1 208.67.222.222
setprop net.dns2 208.67.220.220