Bringing up an interface without an IP address

To create a network interface without an IP address at all use the manual method and use pre-up and post-down commands to bring the interface up and down.
This can be necessary, when you like to bridge a VMWare VM to this interface or when it’s connected to a mirror port on the switch for sniffing [...]

apt - Fix GPG error

When doing an apt-get update to refresh index files from their sources, the indexes of available packages are fetched from the location(s) specified in /etc/apt/sources.list
Sometimes you will see an error like that:

debian:~# apt-get update
Get:1 http://www.backports.org etch-backports Release.gpg [189B]
Hit http://www.backports.org etch-backports Release    
~             
~
(output shortened)
~
~
Hit http://security.debian.org etch/updates/contrib Packages
Hit http://security.debian.org etch/updates/main Sources
Hit http://security.debian.org etch/updates/contrib Sources
Fetched 180kB in 2s (75.2kB/s)
Reading [...]

Building a customized menu

Recently i stumbled across a nice feature in Cisco IOS for building customized menus.
The “menu”-command is really old and was introduced in IOS 10.0
You can i.e. use it for building a menu for CLI-unexperienced staff to simplify troubleshooting.
First of all, you have to configure a little bit AAA  as well as create a user with [...]

Solaris Network Configuration

Solaris Network configuration is a little bit different to Debian.
Because i always forget it, there’s a quick explanation of the necessary steps (taken from here and used with Solaris 5,6,7,8 +9).
/etc-Files
All configuration data, such as IP addresses, gateways, and so on, can be defined and changed at runtime level.
But first of all you have to [...]

Create Wireshark-readable file with tcpdump

Sometimes, it’s necessary to capture packets with tcpdump on a machine without running X-Windows installation.
But most people are not such  cracks, that they can read the confusing output on the console (me included).
To get a better overview, i prefer Wireshark (former known as Ethereal).
With the following tcpdump-flags, you can create a file in .pcap format [...]

ACL log identifiers

When Access Control List Logging is activated on your Cisco device, you will see log entries like that in syslog:

Jun 14 09:49:13 RTR-1 41716: Jun 14 09:49:12.148 MEZ: %SEC-6-IPACCESSLOGP: list 120 denied udp x.x.x.x(1670) -> x.x.x.x(4808), 1 packet
Jun 16 22:14:09 RTR-1 42271: Jun 16 22:14:08.847 MEZ: %SEC-6-IPACCESSLOGDP: list 125 denied icmp x.x.x.x -> x.x.x.x (0/0), [...]

BGP Cease Subcode definition

When you deal with Cisco and BGP, you probably know syslog messages like this:

Apr 11 16:34:38 ROUTER 1026843: Apr 11 16:34:38.010 CET: %BGP-3-NOTIFICATION: received from neighbor 80.x.x.x 6/2 (cease) 0 bytes
Apr 17 14:13:41 ROUTER 30082: Apr 17 14:13:41.126 CET: %BGP-3-NOTIFICATION: received from neighbor 80.x.x.x 6/0 (cease) 0 bytes
Apr 27 05:30:39 ROUTER 1028828: Apr 27 05:30:39.833 [...]

Convert dBm to milliwatts (mW)

Sometimes you have to convert a dBm value to milliwatts, e.g. when you retrieve the output power of a laser or a xDSL port…
You can calculate these values with the following formulas or have a look in the attached conversion table.
mW to dBm:              dBm=10*log10(P/1mW)
dBm to mW:              mW=10(dBm/10)
dBm to mW conversion table

dBm
mW
dBm
mW
dBm
mW
dBm
mW
dBm
mW

0.0
1.00000
0.1
1.02329
0.2
1.04713
0.3
1.07152
0.4
1.09648

0.5
1.12202
0.6
1.14815
0.7
1.17490
0.8
1.20226
0.9
1.23027

1.0
1.2589
1.1
1.2882
1.2
1.3183
1.3
1.3490
1.4
1.3804

1.5
1.4125
1.6
1.4454
1.7
1.4791
1.8
1.5136
1.9
1.5488

2.0
1.5849
2.1
1.6218
2.2
1.6596
2.3
1.6982
2.4
1.7378

2.5
1.7783
2.6
1.8197
2.7
1.8621
2.8
1.9055
2.9
1.9498

3.0
1.9953
3.1
2.0417
3.2
2.0893
3.3
2.1380
3.4
2.1878

3.5
2.2387
3.6
2.2909
3.7
2.3442
3.8
2.3988
3.9
2.4547

4.0
2.5119
4.1
2.5704
4.2
2.6303
4.3
2.6915
4.4
2.7542

4.5
2.8184
4.6
2.8840
4.7
2.9512
4.8
3.0200
4.9
3.0903

5.0
3.1623
5.1
3.2359
5.2
3.3113
5.3
3.3884
5.4
3.4674

5.5
3.5481
5.6
3.6308
5.7
3.7154
5.8
3.8019
5.9
3.8905

6.0
3.9811
6.1
4.0738
6.2
4.1687
6.3
4.2658
6.4
4.3652

6.5
4.4668
6.6
4.5709
6.7
4.6774
6.8
4.7863
6.9
4.8978

7.0
5.0119
7.1
5.1286
7.2
5.2481
7.3
5.3703
7.4
5.4954

7.5
5.6234
7.6
5.7544
7.7
5.8884
7.8
6.0256
7.9
6.1660

8.0
6.3096
8.1
6.4565
8.2
6.6069
8.3
6.7608
8.4
6.9183

8.5
7.0795
8.6
7.2444
8.7
7.4131
8.8
7.5858
8.9
7.7625

9.0
7.9433
9.1
8.1283
9.2
8.3176
9.3
8.5114
9.4
8.7096

9.5
8.9125
9.6
9.1201
9.7
9.3325
9.8
9.5499
9.9
9.7724

10.0
10.0000
10.1
10.2329
10.2
10.4713
10.3
10.7152
10.4
10.9648

10.5
11.2202
10.6
11.4815
10.7
11.7490
10.8
12.0226
10.9
12.3027

11.0
12.5893
11.1
12.8825
11.2
13.1826
11.3
13.4896
11.4
13.8038

11.5
14.1254
11.6
14.4544
11.7
14.7911
11.8
15.1356
11.9
15.4882

12.0
15.8489
12.1
16.2181
12.2
16.5959
12.3
16.9824
12.4
17.3780

12.5
17.7828
12.6
18.1970
12.7
18.6209
12.8
19.0546
12.9
19.4984

13.0
19.9526
13.1
20.4174
13.2
20.8930
13.3
21.3796
13.4
21.8776

13.5
22.3872
13.6
22.9087
13.7
23.4423
13.8
23.9883
13.9
24.5471

14.0
25.1189
14.1
25.7040
14.2
26.3027
14.3
26.9153
14.4
27.5423

14.5
28.1838
14.6
28.8403
14.7
29.5121
14.8
30.1995
14.9
30.9030

15.0
31.6228
15.1
32.3594
15.2
33.1131
15.3
33.8844
15.4
34.6737

15.5
35.4813
15.6
36.3078
15.7
37.1535
15.8
38.0189
15.9
38.9045

16.0
39.8107
16.1
40.7380
16.2
41.6869
16.3
42.6580
16.4
43.6516

16.5
44.6684
16.6
45.7088
16.7
46.7735
16.8
47.8630
16.9
48.9779

17.0
50.1187
17.1
51.2861
17.2
52.4807
17.3
53.7032
17.4
54.9541

17.5
56.2341
17.6
57.5440
17.7
58.8844
17.8
60.2560
17.9
61.6595

18.0
63.0957
18.1
64.5654
18.2
66.0693
18.3
67.6083
18.4
69.1831

18.5
70.7946
18.6
72.4436
18.7
74.1310
18.8
75.8578
18.9
77.6247

19.0
79.4328
19.1
81.2831
19.2
83.1764
19.3
85.1138
19.4
87.0964

19.5
89.1251
19.6
91.2011
19.7
93.3254
19.8
95.4993
19.9
97.7237

20.0
100.0000
20.1
102.3293
20.2
104.7129
20.3
107.1519
20.4
109.6478

20.5
112.2018
20.6
114.8154
20.7
117.4898
20.8
120.2264
20.9
123.0269

21.0
125.8925
21.1
128.8250
21.2
131.8257
21.3
134.8963
21.4
138.0384

21.5
141.2538
21.6
144.5440
21.7
147.9108
21.8
151.3561
21.9
154.8817

22.0
158.4893
22.1
162.1810
22.2
165.9587
22.3
169.8244
22.4
173.7801

22.5
177.8279
22.6
181.9701
22.7
186.2087
22.8
190.5461
22.9
194.9845

23.0
199.5262
23.1
204.1738
23.2
208.9296
23.3
213.7962
23.4
218.7762

23.5
223.8721
23.6
229.0868
23.7
234.4229
23.8
239.8833
23.9
245.4709

24.0
251.1886
24.1
257.0396
24.2
263.0268
24.3
269.1535
24.4
275.4229

24.5
281.8383
24.6
288.4032
24.7
295.1209
24.8
301.9952
24.9
309.0295

25.0
316.2278
25.1
323.5937
25.2
331.1311
25.3
338.8442
25.4
346.7369

25.5
354.8134
25.6
363.0781
25.7
371.5352
25.8
380.1894
25.9
389.0451

26.0
398.1072
26.1
407.3803
26.2
416.8694
26.3
426.5795
26.4
436.5158

26.5
446.6836
26.6
457.0882
26.7
467.7351
26.8
478.6301
26.9
489.7788

27.0
501.1872
27.1
512.8614
27.2
524.8075
27.3
537.0318
27.4
549.5409

27.5
562.3413
27.6
575.4399
27.7
588.8437
27.8
602.5596
27.9
616.5950

28.0
630.9573
28.1
645.6542
28.2
660.6934
28.3
676.0830
28.4
691.8310

28.5
707.9458
28.6
724.4360
28.7
741.3102
28.8
758.5776
28.9
776.2471

29.0
794.3282
29.1
812.8305
29.2
831.7638
29.3
851.1380
29.4
870.9636

29.5
891.2509
29.6
912.0108
29.7
933.2543
29.8
954.9926
29.9
977.2372

30
1000.000
31
1258.925
32
1584.893
33
1995.262
34
2511.886

35
3162.278
36
3981.072
37
5011.872
38
6309.573
39
7943.282

40
10000.00
41
12589.25
42
15848.93
43
19952.62
44
25118.86

45
31622.78
46
39810.72
47
50118.72
48
63095.73
49
79432.82

Using apt with proxy

If you are using APT (Advanced Package Tool) and you are bound to use a proxy server to connect to the internet, you have to configure it as follows.
If not existent, you have to create the file /etc/apt/apt.conf

touch /etc/apt/apt.conf

Now insert the following line…

Acquire::http::Proxy http://username:password@proxy:8080;

Please adjust the parameters to your requirements.
When you try “apt-get update”, it [...]

JunOS - Recover BGP password

When you need to recover missing BGP MD5 password on Juniper routers, you have the possibility to extract it from a specific file.
First, you have to start a shell:

alex@M10> start shell
% su -
Password:
root@M10%

After changing to the root user, you have the necessary permissions to view the file /var/etc/keyadmin.conf

root@M10% cd /var/etc/
root@M10% more keyadmin.conf
tcp 179 0.0.0.0 <IP [...]