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27.02.2013

Howto generate DH parameters for OpenVPN

openssl gendh -out dh4096.pem 4096

18:29 | Linux | Permalink

25.02.2013

Orange Routing 2

I did another test of the Orange Routing.
Running a traceroute to my server in Zurich and one to my vhost in Frankfurt.
First another version of the already familier traceroute to my server in Zurich:

HOST: Andreass-MacBook-Pro.local  Loss%   Snt   Last   Avg  Best  Wrst StDev
  1.|-- 172.20.10.1                0.0%     5    8.0   3.7   2.1   8.0   2.5
  2.|-- 10.8.8.67                  0.0%     5  174.8 114.9  56.7 205.6  69.8
  3.|-- 10.8.12.10                 0.0%     5  126.8 108.4  67.7 171.3  42.8
  4.|-- 192.168.249.201            0.0%     5   73.4  82.7  61.9 111.5  20.5
  5.|-- 192.168.253.191            0.0%     5   54.0  64.9  54.0  75.9   9.3
  6.|-- 192.168.250.203            0.0%     5   64.7  69.2  57.3  79.2   8.4
  7.|-- 10.10.10.10                0.0%     5   56.8  65.5  56.8  72.1   7.7
  8.|-- 10.255.200.1               0.0%     5   65.9  87.3  60.1 146.6  35.1
  9.|-- pos0-1-1-1.gencr1.geneve.  0.0%     5   84.8 117.1  76.4 162.5  36.9
 10.|-- pos14-0-1.pascr4.paris.op  0.0%     5   88.1 118.0  88.1 168.3  36.7
 11.|-- ge6-0-0.br2.par2.alter.ne  0.0%     5   76.5  90.5  76.5 109.1  12.0
 12.|-- so-2-3-0.xt2.zur3.alter.n  0.0%     5   76.8 109.1  76.8 203.2  53.1
 13.|-- pos2-0.gw4.zur4.alter.net  0.0%     5   88.8  98.7  84.3 143.4  25.2
 14.|-- uch200193-gw.customer.alt  0.0%     5   90.7  85.3  74.1  93.5   8.0
 15.|-- whale29.open.ch            0.0%     5   88.9  97.7  88.9 104.7   6.3
 16.|-- orca8.open.ch              0.0%     5   90.8  94.8  90.8 102.8   4.9
 17.|-- real.jaggi.info           20.0%     5  234.8 130.0  92.8 234.8  69.9

Now the traceroute to the vhost in Frankfurt:

HOST: Andreass-MacBook-Pro.local  Loss%   Snt   Last   Avg  Best  Wrst StDev
  1.|-- 172.20.10.1                0.0%     5   15.2  13.1   1.9  44.5  18.4
  2.|-- 10.8.8.115                 0.0%     5   72.6  74.0  67.2  81.3   6.8
  3.|-- 10.8.12.10                 0.0%     5   80.7  75.0  64.0  89.6  10.3
  4.|-- 192.168.249.201            0.0%     5   65.1  78.9  65.1  94.0  12.3
  5.|-- 192.168.253.191            0.0%     5   73.1  70.4  66.5  73.3   2.8
  6.|-- 192.168.250.203            0.0%     5   69.5  73.9  66.3  86.6   7.7
  7.|-- 10.10.10.10                0.0%     5   67.0  72.7  67.0  80.0   4.9
  8.|-- 10.255.200.1               0.0%     5   70.9  74.4  69.7  86.4   7.0
  9.|-- pos0-1-1-1.gencr1.geneve.  0.0%     5   77.2  83.4  75.9  99.4   9.4
 10.|-- pos3-1-0.zurcr1.zurich.op  0.0%     5   83.8 103.2  83.8 146.9  26.3
 11.|-- pos0-9-4-0.ffttr1.frankfu  0.0%     5  102.9 103.6  98.7 108.8   4.9
 12.|-- leaseweb-9.gw.opentransit  0.0%     5   87.6  88.8  85.3  93.2   3.0
 13.|-- te3-1.core-2.fra.leaseweb  0.0%     5   85.4  91.5  85.4 106.1   8.5
 14.|-- hosted-by.leaseweb.com     0.0%     5   90.2  94.1  84.7 112.5  11.0
 15.|-- ???                       100.0     5    0.0   0.0   0.0   0.0   0.0
 16.|-- 0.jaggi.info              20.0%     5   89.9 117.5  86.3 205.5  58.7

As you can see, the RTT is higher for the server in Zurich than for the vhost in Frankfurt! (keep in mind that source of these measurement is my laptop in the train 8 minutes away from Zurich now)

So Orange has higher latency to hosts in the same region/city than to hosts in another country which are more than 350km away. :-(
The next time I choose a mobile provider it might be good to analyse its BGP peerings and routing policies first...

13:20 | Networking | Permalink

Orange Routing

While in the train from Bern to Zurich, I did a traceroute towards the server which currently hosts this weblog (it is located at Open Systems in Zurich). The connection starts on my laptop and is thethered via my cell to the Orange backbone.

HOST: Andreass-MacBook-Pro.local  Loss%   Snt   Last   Avg  Best  Wrst StDev
  1.|-- 172.20.10.1                0.0%     5    2.0  12.1   1.7  33.2  14.6
  2.|-- 10.8.8.67                  0.0%     5   52.2 373.4  52.2 1241. 504.8
  3.|-- 10.8.12.10                 0.0%     5   50.9 347.4  50.9 1143. 453.3
  4.|-- 192.168.249.201            0.0%     5   51.2 282.7  51.2 1042. 426.8
  5.|-- 192.168.253.191            0.0%     5   51.2 226.2  44.5 942.2 400.3
  6.|-- 192.168.250.203            0.0%     5   51.4 206.7  37.9 847.5 358.2
  7.|-- 10.10.10.10                0.0%     5   50.0 181.4  29.6 746.9 316.2
  8.|-- 10.255.200.1               0.0%     5   50.0 172.2  36.9 645.6 264.9
  9.|-- 193.251.248.145            0.0%     4   60.2  59.8  46.2  81.9  15.8
 10.|-- 193.251.240.53             0.0%     4   70.0  76.4  64.9 101.6  16.9
 11.|-- 146.188.112.77             0.0%     4   70.4  74.0  69.2  83.8   6.7
 12.|-- 146.188.5.1                0.0%     4   70.6  71.7  58.1  88.1  12.3
 13.|-- 146.188.4.194              0.0%     4   70.5  61.9  51.6  70.9  10.2
 14.|-- 146.188.64.74              0.0%     4   71.3  69.2  58.8  75.4   7.2
 15.|-- 213.156.230.29             0.0%     4   71.5  78.3  62.6 108.9  20.7
 16.|-- 213.156.229.8              0.0%     4   72.2  75.2  70.4  81.9   5.1
 17.|-- 213.156.229.222           25.0%     4   80.8  76.2  61.2  86.5  13.3

You can see that the traffic is passed through 8 different routers inside the Orange backbone (using IPs from all three RFC1918 ranges...) before it is let onto the Internet.
And then the real fun starts (let's use DNS names for this):

HOST: Andreass-MacBook-Pro.local  Loss%   Snt   Last   Avg  Best  Wrst StDev
  1.|-- 172.20.10.1                0.0%     5    2.0  12.2   1.9  33.3  14.5
  2.|-- 10.8.8.67                  0.0%     5   44.2 345.6  27.0 1167. 494.2
  3.|-- 10.8.12.10                 0.0%     5   52.2 308.9  27.0 1104. 462.4
  4.|-- 192.168.249.201            0.0%     5   33.4 264.9  27.2 1014. 427.1
  5.|-- 192.168.253.191            0.0%     5   30.3 227.5  27.3 952.9 406.4
  6.|-- 192.168.250.203            0.0%     5   50.4 200.7  27.0 860.0 368.7
  7.|-- 10.10.10.10                0.0%     5   72.4 193.5  30.5 779.2 327.8
  8.|-- 10.255.200.1               0.0%     5   31.8 166.8  27.6 688.0 291.5
  9.|-- pos0-1-1-1.gencr1.geneve.  0.0%     4   50.8  55.0  47.6  67.1   8.6
 10.|-- pos14-0-1.pascr4.paris.op  0.0%     4   61.0  64.4  57.7  78.5   9.5
 11.|-- ge6-0-0.br2.par2.alter.ne  0.0%     4   70.8  56.3  48.4  70.8   9.9
 12.|-- so-2-3-0.xt2.zur3.alter.n  0.0%     4  108.9  65.6  48.0 108.9  29.2
 13.|-- pos2-0.gw4.zur4.alter.net  0.0%     4   51.7  55.5  50.3  68.8   8.8
 14.|-- uch200193-gw.customer.alt  0.0%     4  171.8  83.6  50.7 171.8  58.8
 15.|-- whale29.open.ch            0.0%     4  132.1  90.0  59.2 132.1  32.7
 16.|-- orca8.open.ch              0.0%     4   72.4  66.8  58.6  73.5   7.3
 17.|-- real.jaggi.info           25.0%     4   80.2  64.7  56.2  80.2  13.4

As we see, Orange injects their mobile data traffic into the Internet in Geneva (pos0-1-1-1.gencr1.geneve.).
Then it is first sent to Paris (pas14-0-1.pascr4.paris.op and ge6-0-0.br2.par2.alter.ne) and from there back to Zurich (so-2-3-0.xt2.yur3.alter.n and all the following hosts).

I can kind of understand that the traffic is routed via Geneva (main Orange infrastructure is there), but why is it sent to Paris? (especially since Geneva<->Zurich is the main Internet connection inside Switzerland where most of the countries fiber is buried).

I guess this explains why my mobile data speed is not always as fast as I like it to be...

12:34 | Networking | Permalink

18.02.2013

Administrative Distance

When using more than one dynamic routing protocol, make sure to know their administrative distance.

Further it is usually a bad idea to redistribute routes from a dynamic routing protocol into another one with a lower administrative distance. Especially when having multiple handover points between the two protocols.

08:39 | Networking | Permalink

17.02.2013

I ♡ snow

17:31 | Misc | Permalink

14.02.2013

Computer Science

Computer Science
via boingboing.net

18:07 | Misc | Permalink

13.02.2013

Updated HAVP blacklist script

The HAVP blacklist script chocked on some entries from PhishTank. These issues have been fixed with some more sed magic and I've put and updated version of the script on Github.

18:02 | Linux | Permalink

Verify a BGP MD5 password before session turnup

When setting up a new BGP peering, you may want to test if your peering partner uses the correct MD5 password without bringing up your side of the session.
For this the tcpdump option -M can be used to supply the MD5 password when sniffing the traffic of the new peer:

tcpdump -ni eth0 -M MyBgPMd5PaSsWoRd tcp port 179

tcpdump will then verify the MD5 signature for every packet where it finds a MD5 signature TCP option as specified in RFC2385.
In the output you will see md5valid for packets where your password matches the MD5 signature or md5invalid for packets where your password does not match the MD5 signature.
If you see neither md5valid nor md5invalid then the peer did not configure any MD5 BGP password.

If you want to check for mismatching MD5 passwords after you bring up the BGP session, just look into the kernel log. Linux reports invalid MD5 TCP signatures like this:

MD5 Hash failed for (1.2.3.4, 56789)->(1.2.3.5, 179)

09:02 | Networking | Permalink

05.02.2013

Configure unattached Bridge Interfaces in Debian

When working with virtualization technologies like KVM on Debian, you might need to configure bridge interfaces which are not attached to a physical interfaces (for example for a non-routed management network or similar).
Debian uses the directive bridge_ports in /etc/network/interfaces to indicate whether an interface is a bridge interface or not. The syntax checker does not accept an empty bridge_ports directive since he expects a list of physical interfaces to attach to the bridge interface.

When needing a bridge interface without any physical interfaces attached, usually people configure this interface by hand or with a special script.
Since I manage /etc/network/interfaces with my Puppet module, I would like to use it to configure all network interfaces including the unattached bridge interfaces.
It turns out that this can be done by passing none as parameter for the bridge_ports directive like this:

interface br0 inet static
	address 192.0.2.1
	netmask 255.255.255.0
	bridge_ports none

08:42 | Linux | Permalink