Technical data

B. Appendixes to optional packages
This allows to notice that a packet first reaches fli4l (first line), then the other end of the
tunnel (second row) and finally the global IPv6 internet (from the third line):
C:\>tracert 2001:bf0:c000:a::2:132
Route tracing to virtualhost.in-berlin.de [2001:bf0:c000:a::2:132]
on a maximum of 30 hops:
1 <1 ms <1 ms <1 ms garm.example.org [2001:db8:13da:1::1]
2 70 ms 79 ms 71 ms gw-1362.ham-01.de.sixxs.net [2001:db8:900:551::1]
3 67 ms 71 ms 76 ms 2001:db8:800:1003::209:55
4 68 ms * 70 ms 2001:db8:1:0:87:86:71:240
5 69 ms * 71 ms 2001:db8:1:0:87:86:77:67
6 72 ms * 71 ms 2001:db8:1:0:86:87:77:81
7 71 ms * 71 ms 2001:db8:1:0:87:86:77:83
8 90 ms * 81 ms 2001:db8:1:0:87:86:77:62
9 84 ms * 88 ms 2001:db8:1:0:87:86:77:71
10 99 ms 83 ms 83 ms 2001:db8:1:0:87:86:77:249
11 94 ms 87 ms 87 ms 20gigabitethernet4-3.core1.fra1.he.net
[2001:7f8::1b1b:0:1]
12 96 ms 99 ms 99 ms 10gigabitethernet1-4.core1.ams1.he.net
[2001:470:0:47::1]
13 105 ms 108 ms 107 ms 2001:7f8:8:5:0:73e6:0:1
14 106 ms 107 ms 104 ms virtualhost.in-berlin.de [2001:bf0:c000:a::2:132]
Tracing ended.
B.12. ISDN
B.12.1. Technical Details About Dial-In And Routing With ISDN
This chapter is interesting for those who want to know what is happening ’under the hood’,
having special wishes for configuration or simply looking for solutions to their problems. All
others are not encouraged to read this chapter.
After establishing a connection to the provider the ipppd daemon that has made the con-
nection newly configures the interface to set the negotiated IP addresses. The linux kernel
automatically sets corresponding routes for remote IP address and netmask. Existing special
routes will be deleted. If no netmask is given the ipppd derives it from the remote IP netmask
(Class A, B and C subnets will be used here). The vanishing of existing and appearing of new
routes has raised problems time and time again:
• Company networks were unaccessible because of routes vanishing or being overlayed by
newly set ones
• Interfaces were dialing in apparently without cause because a packet was routed by the
kernel to another interface instead of the default route
• ...
Because of that it is tried to avoid unwanted routes.
The following things will be changed to achieve this:
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