Connected to VPN, no DNS servers at all

Question

So I'm running a cisco 30005 VPN concentrator.

Network Diagram:

So the cisco linux client works fine, I can ping google, and traceroute goes through 192.168.1.1, which is my router. It does normal name resolution stuff on all the steps.

But when a windows client connects, no hostnames can be resolved. It's not even internal hostnames(I have no internal DNS stuff), it's all hostnames. I cannot ping google.com, but I can ping 173.194.46.38.

With tracert, the first step is the public interface of the VPN, then the router, and then onwards to google(No name resolution, just IPs).

Linux, connected to VPN
mark@Laptop:~$ traceroute google.com
traceroute to google.com (74.125.225.37), 30 hops max, 60 byte packets
 1  * * *
 2  192.168.1.1 (192.168.1.1)  9.569 ms  9.616 ms  9.665 ms
 3  mx80-07-001-resnet-wads-5.tc.mtu.edu (141.219.232.2)  13.059 ms  13.102 ms  13.119 ms
 4  mx960-07-001-rtr-z03-eerc.tc.mtu.edu (141.219.183.122)  13.501 ms  17.128 ms  17.147 ms
 5  mx80-07-002.tc.mtu.edu (141.219.183.97)  17.540 ms  20.541 ms  20.581 ms
 6  xe-0-0-3.hgtn-cor-mtu.mich.net (207.75.40.9)  20.597 ms  14.320 ms  14.290 ms
 7  vlan47.iron-mt-gigsw1.mich.net (198.108.22.41)  21.427 ms  18.776 ms  18.793 ms
 8  xe-5-0-1x69.eq-chi2.mich.net (198.108.22.97)  36.628 ms  38.027 ms  34.386 ms
 9  207.72.112.46 (207.72.112.46)  38.075 ms  37.717 ms  34.649 ms
10  209.85.254.120 (209.85.254.120)  38.147 ms  35.094 ms  34.896 ms
11  209.85.250.28 (209.85.250.28)  34.962 ms  28.178 ms  30.715 ms
12  ord08s06-in-f5.1e100.net (74.125.225.37)  30.733 ms  29.842 ms  28.085 ms

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Windows, connected to VPN
C:\Users\Mark>tracert 173.194.46.38

Tracing route to 173.194.46.38 over a maximum of 30 hops

  1     2 ms     2 ms     2 ms  141.219.233.110
  2     2 ms     2 ms     3 ms  192.168.1.1
  3     5 ms     2 ms     2 ms  141.219.232.2
  4     3 ms     2 ms     2 ms  141.219.183.122
  5     2 ms     2 ms     2 ms  141.219.183.97
  6     3 ms     2 ms     2 ms  207.75.40.9
  7     8 ms     7 ms     7 ms  198.108.22.41
  8    25 ms    25 ms    25 ms  198.108.22.97
  9    25 ms    25 ms    25 ms  207.72.112.46
 10    25 ms    25 ms    26 ms  209.85.254.120
 11    26 ms    26 ms    26 ms  209.85.243.53
 12    26 ms    25 ms    25 ms  173.194.46.38

Trace complete.

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VPN, from public interface. I can't figure out how to have it try from the private interface.
Traceroute start...
traceroute: Warning: google.com has multiple addresses; using 173.194.46.110
traceroute to google.com (173.194.46.110), 30 hops max, 40 byte packets
source interface: Public (141.219.233.110)
 1  mx80-07-001-resnet-wads-5.tc.mtu.edu (141.219.232.2)  0.388 ms  0.359 ms  0.342 ms
 2  mx960-07-001-rtr-z03-eerc.tc.mtu.edu (141.219.183.122)  0.360 ms  0.354 ms  0.327 ms
 3  mx80-07-002.tc.mtu.edu (141.219.183.97)  0.442 ms  0.406 ms  0.450 ms
 4  xe-0-0-3.hgtn-cor-mtu.mich.net (207.75.40.9)  0.437 ms  0.440 ms  0.403 ms
 5  vlan47.iron-mt-gigsw1.mich.net (198.108.22.41)  5.54 ms  6.83 ms  6.62 ms
 6  xe-5-0-1x69.eq-chi2.mich.net (198.108.22.97)  23.2 ms  23.1 ms  23.4 ms
 7  207.72.112.46 (207.72.112.46)  23.5 ms  23.2 ms  23.4 ms
 8  209.85.254.128 (209.85.254.128)  23.5 ms  27.5 ms  23.6 ms
 9  209.85.245.225 (209.85.245.225)  23.8 ms  23.8 ms  23.9 ms
10  ord08s13-in-f14.1e100.net (173.194.46.110)  23.5 ms  23.7 ms  23.4 ms
Trace complete.

I have the client's DNS servers to 8.8.8.8 and 8.8.4.4 in the interface IPv4 settings, and the router's DNS servers set to that as well.

The routing table for the VPN is

Address         Mask            Next Hop        Interface   Protocol    Age     Metric
0.0.0.0         0.0.0.0         141.219.232.1   2           Default     0       1
141.219.232.0   255.255.254.0   0.0.0.0         2           Local       0       1
192.168.1.0     255.255.255.0   0.0.0.0         1           Local       0       1

I don't really understand what this means. I assume the introductory networking class I'll hopefully be taking next fall will be helpful with this, but it's less than useful right now.

.

End goal here is just to feel better about using public wifi somewhere, just so I can run everything through a VPN. Also, access windows shares.

So what can I do to help figure out what I'm doing wrong?

Answer 1

I imagine that name resolution works fine when your windows pcs connect to the internet without passing throught the VPN. If so, it means the problem lies in the handling of traffic on port 53 in your schoold network, and you may try getting around that by adding specific routes to Google's nameservers through your router (192.168.1.1), whch would keep DNS requests out of your school VPN. You may try this as an experiment, keeping in mind that you must explicitly add 8.8.4.4/8.8.8.8 in the IPv4 settings, besides providing the routes.

This strange behaviour is associated with a security practice aimed at preventing static IPs on the LAN, because these are harder to identify.