DNS not set during PPP connection

[Jim Kirkpatrick]

Binary package hint: ppp

Note: This bug is a follow on from bug 258801 (Gets bogus DNS servers during PPP negotiation). However, it IS NOT a duplicate of that bug as it is largely solved for most people. Alexander Sack requested someone create a new bug to describe this 'corner case', so here it is...

Description:
About 50% of the time I connect to my 3G network and though the connection appears ok and Network Manager tells me all's good, the connection is useless because there is no functioning DNS. For me, recreating this bug is simply a case of connecting as normal. Sometimes everything is good, sometimes it's not and there are no DNS entries at all under 'Connection Information'. It is quite possible to have to disconnect/reconnect many times in order to get a working connection.

Hardware, Software & Other Info:
* I'm using a Huawei E169 3G USB modem to connect to the 3 (Three) UK network.
* Intrepid 8.10 with PPP 2.4.4rel-10ubuntu2.8.10.1
* Connects first time, every time under windows with exactly the same hardware and network.

Attached is a recent syslog showing two failed connections and a successful one.

[emilio (emiliomaggio)]

I can confirm this bug. I have also tested two different laptops (Dell Inspiron 6000 and Dell Latitude E4300) and in both configurations the DNS connection is not consistent.

I travel a lot and I have noted that bad connections tend to happen always in the same places? Is this a cell related problem? I.e. ppp is not capable of receiving the DNS for certain cells?

[Alexander Sack (asac)]

any chance to test this with the latest jaunty (maybe livecd)?

[Jim Kirkpatrick (jim-kirkpatrick)]

Hi Alexander, I'm posting this from the Jaunty alpha 5 LiveCD...

The same problem exists; I had to disconnect and reconnect to get working DNS. I've tried the connection a few times and it seems the same as in Intrepid.

ppp version: 2.4.5~git20081126t100229-0ubuntu2

syslog attached with numerous failed and valid connections (the give away is that NTP can do an update vs. complaining about no servers)

Best, Jim

[Jim Kirkpatrick (jim-kirkpatrick)]

Ok, now I'm using Jaunty I can provide more information and a work-around that renders this bug fixed for me...

I think the DNS problem is actually with 3 Mobile UK's wobbly 3G network rather than a problem with any component within Jaunty. I say this because I've recently moved house and my Windows-using housemates borrow the connection occasionally and do sometimes have broken DNS. I'd never had that problem in Windows, but then I've only connected under Windows about a dozen times.

So, the work around comes from the fact that PPP in Jaunty does honour the manually entered DNS servers, whereas Intrepid always seemed to ignore them. I fixed this issue by bypassing 3 Mobile's DNS servers and using OpenDNS instead - like so:

1) Right click the network manager icon in the system tray, choose "Edit connections"
2) Go to the "Mobile Broadband" tab and edit the relevant connection
3) Go to 3rd "IPv4 Settings" tab, change "Method" drop-down to "Automatic (PPP) addresses only"
4) Enter "208.67.222.222, 208.67.220.220" in the "DNS Servers" box, click "Apply" and then "Close"

The above means my connection always has good DNS, so this bug/problem is indeed fixable.

[Markus Kopp (mkopp)]

I had the same problem in Jaunty (Eplus in Germany with NetworkManager and Sierra MC8775 Modem). On the first dial i don't get DNS. After disconnect and reconnect it worked. I have changed ipcp-max-failure to 30 in /etc/ppp/options. This is a workaround witch works for me.

[Peter Cherriman (pjcherriman)]

My vodafone ks3565 (huawei e220/e270) worked perfectly in jaunty, but since Ive installed karmic, I don't get any DNS servers detected in 2 out 3 connection attempts. This happens on two different netbooks with the same dongle. I am currently using a workaround of using the opendns servers, by setting them in network manager,

[strowger (strowger)]

I'm using a Huawei E1550 with Karmic amd64.

I see the same problem of invalid DNS servers on the UK "3", Vodafone, and O2 networks. I don't have an easy way to test the others just now but it's fair to say it's not network specific.

I'm guessing this problem is actually still very widespread, but most people aren't seeing it because they're using NetworkManager and it's setting up DNS for them.

Markus Kopp's workaround - "ipcp-max-failure 30" - works for me.