[Samsung Galaxy Mini] Doc_cheilvenerdi.org:
Reverse Tethering... 90%

I obtained the same result disabling Data Connection from the phone and activating the "USB Tethering" from the Wireless Settings Menu...

The usb0 network interface was created "on his own" with 192.168.42.129 address, no route or DNS servers...

Finally I completed the setup this way:

busybox route delete default
busybox route add default gw 192.168.42.119 usb0
setprop net.usb0.dns1 208.67.222.222
setprop net.usb0.dns2 208.67.220.220
setprop net.dns1 208.67.222.222
setprop net.dns2 208.67.220.220

I used OpenDNS server (provider's addresses should be a faster choice, anyway...)

P.S. On the PC Side (Linux for me) I setup its usb interface with 192.168.42.119 address and everything needed to act as a router for the Phone via Usb (the technique is called MASQUERADING)

In the notify Bar I also see this USB Tethering Blue Icon:

Like you, I can browse but without your annoying alert (can you post a screenshot?) in each page...

Market up and running but NO DOWNLOAD MODE!

...working on... but I think it's a client/server authentication error:

I sniffed with tcpdump the working 3G Data connection while starting a download and I read this packet flow:

[size=1]No. Time Source Destination Protocol Length Info
14 11.682225 ???.???.???.??? 173.194.35.42 TLSv1 148 [color=red]Client Hello[/color]
15 12.175937 173.194.35.42 ???.???.???.??? TCP 68 https > 54635 [ACK] Seq=1 Ack=81 Win=5696 Len=0 TSval=751940065 TSecr=753693
16 12.596495 173.194.35.42 ???.???.???.??? TLSv1 1366 [color=red]Server Hello[/color]
17 12.596765 ???.???.???.??? 173.194.35.42 TCP 68 54635 > https [ACK] Seq=81 Ack=1299 Win=7836 Len=0 TSval=753785 TSecr=751940065
18 12.606427 173.194.35.42 ???.???.???.??? TLSv1 1037 [color=red]Certificate, Server Hello Done[/color]
19 12.606637 ???.???.???.??? 173.194.35.42 TCP 68 54635 > https [ACK] Seq=81 Ack=2268 Win=10432 Len=0 TSval=753786 TSecr=751940065
20 12.834427 ???.???.???.??? 173.194.35.42 TLSv1 254 [color=red]Client Key Exchange, Change Cipher Spec, Encrypted Handshake Message[/color]
21 12.988245 173.194.35.42 ???.???.???.??? TLSv1 115 [color=red]Change Cipher Spec, Encrypted Handshake Message[/color]
22 12.988614 ???.???.???.??? 173.194.35.42 TCP 68 54635 > https [ACK] Seq=267 Ack=2315 Win=10432 Len=0 TSval=753824 TSecr=751940925
25 13.276592 ???.???.???.??? 173.194.35.42 TLSv1 1045 Application Data
26 13.566400 173.194.35.42 ???.???.???.??? TCP 68 https > 54635 [ACK] Seq=2315 Ack=1244 Win=8704 Len=0 TSval=751941505 TSecr=753853
27 14.066927 173.194.35.42 ???.???.???.??? TLSv1 1366 Application Data
28 14.067332 ???.???.???.??? 173.194.35.42 TCP 68 54635 > https [ACK] Seq=1244 Ack=3613 Win=13028 Len=0 TSval=753932 TSecr=751941990
29 14.067570 173.194.35.42 ???.???.???.??? TLSv1 120 Application Data[/size]

I just obscured (???) my IP address...

The SSL/TLS Starting sequence (red codes) is right and then the download phase begins (Following TLS/TCP application Encrypted Data)...

Passing through my PC, MASQUERADING router, I read:

[size=1]No. Time Source Destination Protocol Length Info
13 1.511228 192.168.42.129 74.125.232.111 TLSv1 146 [color=red]Client Hello[/color]
14 1.531984 192.168.42.129 74.125.232.111 TLSv1 252 [color=red]Client Key Exchange, Change Cipher Spec, Encrypted Handshake Message[/color]
15 1.608507 74.125.232.111 192.168.42.129 TCP 66 https > 56443 [ACK] Seq=1 Ack=81 Win=5696 Len=0 TSval=2690369789 TSecr=953086
16 1.617640 74.125.232.111 192.168.42.129 TLSv1 1484 [color=red]Server Hello[/color]
17 1.618125 192.168.42.129 74.125.232.111 TCP 66 56443 > https [ACK] Seq=81 Ack=1419 Win=8736 Len=0 TSval=953097 TSecr=2690369789
18 1.650262 74.125.232.111 192.168.42.129 TLSv1 915 [color=red]Certificate, Server Hello Done[/color]
19 1.650721 192.168.42.129 74.125.232.111 TCP 66 56443 > https [ACK] Seq=81 Ack=2268 Win=11572 Len=0 TSval=953100 TSecr=2690369789
20 1.651012 74.125.232.111 192.168.42.129 TLSv1 113 [color=red]Change Cipher Spec, Encrypted Handshake Message[/color]
21 1.651233 192.168.42.129 74.125.232.111 TCP 66 42496 > https [ACK] Seq=267 Ack=2315 Win=11572 Len=0 TSval=953100 TSecr=2690369825
24 1.827602 192.168.42.129 74.125.232.111 TLSv1 252 [color=red]Client Key Exchange, Change Cipher Spec, Encrypted Handshake Message[/color]
25 1.835222 192.168.42.129 74.125.232.111 TLSv1 908 Application Data
26 1.947684 74.125.232.111 192.168.42.129 TLSv1 113 [color=red]Change Cipher Spec, Encrypted Handshake Message[/color]
27 1.948248 192.168.42.129 74.125.232.111 TCP 66 56443 > https [ACK] Seq=267 Ack=2315 Win=11572 Len=0 TSval=953130 TSecr=2690370110
28 2.027650 74.125.232.111 192.168.42.129 TCP 66 https > 42496 [ACK] Seq=2315 Ack=1109 Win=8448 Len=0 TSval=2690370197 TSecr=953118
29 2.045101 192.168.42.129 74.125.232.111 TLSv1 1125 Application Data

... [i]many attempts to handshake... all errors[/i]

210 4.199993 192.168.42.129 74.125.232.111 TCP 66 42496 > https [ACK] Seq=2192 Ack=123167 Win=89548 Len=0 TSval=953355 TSecr=2690372329
211 42.367246 192.168.42.129 74.125.232.111 TLSv1 1136 Application Data
212 42.453136 192.168.42.129 74.125.232.111 TLSv1 1131 Application Data
213 43.857919 192.168.42.129 74.125.232.111 TLSv1 1136 [color=red][b][TCP Retransmission] Application Data[/b][/color]
214 44.037897 192.168.42.129 74.125.232.111 TLSv1 1131 [color=red][b][TCP Retransmission] Application Data[/b][/color]
215 44.368897 192.168.42.129 74.125.232.111 TLSv1 93 [color=red][b]Encrypted Alert[/b][/color]
216 44.395369 192.168.42.129 74.125.232.111 TCP 74 41181 > https [SYN] Seq=0 Win=5840 Len=0 MSS=1460 SACK_PERM=1 TSval=957374 TSecr=0 WS=4
217 44.456978 192.168.42.129 74.125.232.111 TLSv1 93 [color=red][b]Encrypted Alert[/b][/color]
218 44.508727 192.168.42.129 74.125.232.111 TCP 74 50576 > https [SYN] Seq=0 Win=5840 Len=0 MSS=1460 SACK_PERM=1 TSval=957386 TSecr=0 WS=4
219 44.659205 74.125.232.111 192.168.42.129 TCP 66 https > 42496 [ACK] Seq=123167 Ack=3262 Win=12800 Len=0 TSval=2690412843 TSecr=957171
220 44.668776 74.125.232.111 192.168.42.129 TCP 66 https > 56443 [ACK] Seq=14263 Ack=2391 Win=11008 Len=0 TSval=2690412853 TSecr=957180
221 44.739400 74.125.232.111 192.168.42.129 TCP 78 [TCP Dup ACK 219#1] https > 42496 [ACK] Seq=123167 Ack=3262 Win=12800 Len=0 TSval=2690412879 TSecr=957321 SLE=2192 SRE=3262
222 44.740494 74.125.232.111 192.168.42.129 TCP 78 [TCP Dup ACK 220#1] https > 56443 [ACK] Seq=14263 Ack=2391 Win=11008 Len=0 TSval=2690412885 TSecr=957339 SLE=1326 SRE=2391
223 44.740858 74.125.232.111 192.168.42.129 TCP 74 https > 41181 [SYN, ACK] Seq=0 Ack=1 Win=5672 Len=0 MSS=1430 SACK_PERM=1 TSval=2690412886 TSecr=957374 WS=64
224 44.741167 74.125.232.111 192.168.42.129 TCP 74 https > 50576 [SYN, ACK] Seq=0 Ack=1 Win=5672 Len=0 MSS=1430 SACK_PERM=1 TSval=2690412889 TSecr=957386 WS=64
225 44.741228 192.168.42.129 74.125.232.111 TCP 66 41181 > https [ACK] Seq=1 Ack=1 Win=5840 Len=0 TSval=957409 TSecr=2690412886
226 44.741507 192.168.42.129 74.125.232.111 TCP 66 50576 > https [ACK] Seq=1 Ack=1 Win=5840 Len=0 TSval=957409 TSecr=2690412889
227 44.751366 192.168.42.129 74.125.232.111 TLSv1 146 [color=red]Client Hello[/color]

... [i]starting handshake sequence again and again...[/i]
[/size]

This time the starting SSL/TLS sequence (Handshake between Market Server and My Phone) ends up with error messages and retries...

...something goes wrong while exchanging each other the trusting encrypted certificates...

...hmm... I think the solution is outside the bare Tethering Setup... maybe something related to the router MASQUERADING technique and about loosing the trusted relationship between client and server (required by the SSL/TLS protocol)...

...while searching a way to mangle the IP packets flowing through my Linux machine I'll try to pass all the connection through a Proxy Server...

...will it work? I don't know...