Adv-Routing-HOWTO(1).pdf

(246 KB) Pobierz
Linux Advanced Routing & Traffic Control HOWTO
Linux Advanced Routing & Traffic Control HOWTO
Bert Hubert
Netherlabs BV
Gregory Maxwell
Remco van Mook
Martijn van Oosterhout
Paul B Schroeder
Jasper Spaans
Revision History
Revision 1.1
2002−07−22
DocBook Edition
A very hands−on approach to iproute2, traffic shaping and a bit of netfilter.
184432247.001.png
Linux Advanced Routing & Traffic Control HOWTO
Table of Contents
Chapter 1. Dedication. ........................................................................................................................................1
Chapter 2. Introduction. .....................................................................................................................................2
2.1. Disclaimer & License. ......................................................................................................................2
2.2. Prior knowledge. ...............................................................................................................................2
2.3. What Linux can do for you. ..............................................................................................................3
2.4. Housekeeping notes. .........................................................................................................................3
2.5. Access, CVS & submitting updates. .................................................................................................3
2.6. Mailing list. .......................................................................................................................................4
2.7. Layout of this document. ..................................................................................................................4
Chapter 3. Introduction to iproute2. .................................................................................................................5
3.1. Why iproute2?. ..................................................................................................................................5
3.2. iproute2 tour. .....................................................................................................................................5
3.3. Prerequisites. .....................................................................................................................................5
3.4. Exploring your current configuration. ..............................................................................................6
3.4.1. ip shows us our links. ..............................................................................................................6
3.4.2. ip shows us our IP addresses. ..................................................................................................6
3.4.3. ip shows us our routes. ............................................................................................................7
3.5. ARP. ..................................................................................................................................................8
Chapter 4. Rules − routing policy database. ...................................................................................................10
4.1. Simple source policy routing. .........................................................................................................10
4.2. Routing for multiple uplinks/providers.. .........................................................................................11
4.2.1. Split access. ...........................................................................................................................12
4.2.2. Load balancing. .....................................................................................................................13
Chapter 5. GRE and other tunnels. .................................................................................................................14
5.1. A few general remarks about tunnels:. ...........................................................................................14
5.2. IP in IP tunneling. ...........................................................................................................................14
5.3. GRE tunneling. ...............................................................................................................................15
5.3.1. IPv4 Tunneling. .....................................................................................................................15
5.3.2. IPv6 Tunneling. .....................................................................................................................16
5.4. Userland tunnels.. ............................................................................................................................17
Chapter 6. IPv6 tunneling with Cisco and/or 6bone. .....................................................................................18
6.1. IPv6 Tunneling ...............................................................................................................................18
Chapter 7. IPsec: secure IP over the Internet. ...............................................................................................21
Chapter 8. Multicast routing ...........................................................................................................................22
Chapter 9. Queueing Disciplines for Bandwidth Management. ...................................................................24
9.1. Queues and Queueing Disciplines explained. .................................................................................24
9.2. Simple, classless Queueing Disciplines. .........................................................................................25
9.2.1. pfifo_fast ...............................................................................................................................25
9.2.2. Token Bucket Filter. ..............................................................................................................27
9.2.3. Stochastic Fairness Queueing. ...............................................................................................29
i
184432247.002.png
Linux Advanced Routing & Traffic Control HOWTO
Table of Contents
9.3. Advice for when to use which queue. .............................................................................................30
9.4. Terminology. ...................................................................................................................................30
9.5. Classful Queueing Disciplines. .......................................................................................................32
9.5.1. Flow within classful qdiscs & classes. ..................................................................................32
9.5.2. The qdisc family: roots, handles, siblings and parents. .........................................................33
9.5.3. The PRIO qdisc. ....................................................................................................................34
9.5.4. The famous CBQ qdisc. ........................................................................................................36
9.5.5. Hierarchical Token Bucke. ...................................................................................................41
9.6. Classifying packets with filters. ......................................................................................................42
9.6.1. Some simple filtering examples. ...........................................................................................43
9.6.2. All the filtering commands you will normally need.. ............................................................44
9.7. The Intermediate queueing device (IMQ.. .....................................................................................44
9.7.1. Sample configuration. ...........................................................................................................45
Chapter 10. Load sharing over multiple interfaces. ......................................................................................47
10.1. Caveats. .........................................................................................................................................48
10.2. Other possibilities. ........................................................................................................................48
Chapter 11. Netfilter & iproute − marking packets. .....................................................................................49
Chapter 12. Advanced filters for (re−)classifying packets. ...........................................................................50
12.1. The u32 classifier. .........................................................................................................................50
12.1.1. U32 selector. ........................................................................................................................51
12.1.2. General selectors. ................................................................................................................52
12.1.3. Specific selectors. ................................................................................................................53
12.2. The route classifier. .......................................................................................................................53
12.3. Policing filters. ..............................................................................................................................54
12.3.1. Ways to police. ....................................................................................................................54
12.3.2. Overlimit actions. ................................................................................................................55
12.3.3. Examples. ............................................................................................................................55
12.4. Hashing filters for very fast massive filtering.. .............................................................................55
Chapter 13. Kernel network parameters. .......................................................................................................58
13.1. Reverse Path Filtering. ..................................................................................................................58
13.2. Obscure settings. ...........................................................................................................................59
13.2.1. Generic ipv4. .......................................................................................................................59
13.2.2. Per device settings. ..............................................................................................................62
13.2.3. Neighbor policy. ..................................................................................................................63
13.2.4. Routing settings. ..................................................................................................................64
Chapter 14. Advanced & less common queueing disciplines. .......................................................................66
14.1. bfifo/pfifo. .....................................................................................................................................66
14.1.1. Parameters & usage. ............................................................................................................66
14.2. Clark−Shenker−Zhang algorithm (CSZ). .....................................................................................66
14.3. DSMARK. ....................................................................................................................................67
14.3.1. Introduction. ........................................................................................................................67
14.3.2. What is Dsmark related to?. ................................................................................................67
ii
184432247.003.png
Linux Advanced Routing & Traffic Control HOWTO
Table of Contents
14.3.3. Differentiated Services guidelines.. .....................................................................................67
14.3.4. Working with Dsmark. ........................................................................................................68
14.3.5. How SCH_DSMARK works.. ............................................................................................68
14.3.6. TC_INDEX Filter. ...............................................................................................................69
14.4. Ingress qdisc.. ................................................................................................................................71
14.4.1. Parameters & usage. ............................................................................................................71
14.5. Random Early Detection (RED). ..................................................................................................71
14.6. Generic Random Early Detection. ................................................................................................72
14.7. VC/ATM emulation. .....................................................................................................................72
14.8. Weighted Round Robin (WRR). ...................................................................................................72
Chapter 15. Cookbook. .....................................................................................................................................74
15.1. Running multiple sites with different SLAs. ................................................................................74
15.2. Protecting your host from SYN floods. ........................................................................................75
15.3. Rate limit ICMP to prevent dDoS. ................................................................................................76
15.4. Prioritizing interactive traffic. .......................................................................................................76
15.5.1. Traffic flow diagram after implementation. ........................................................................80
15.6.1. Solution ...............................................................................................................................81
& PPtP users). .......................................................................................................................................82
15.8.1. Why it doesn't work well by defaul. ...................................................................................83
15.8.2. The actual script (CBQ). .....................................................................................................84
15.8.3. The actual script (HTB). ......................................................................................................86
15.9. Rate limiting a single host or netmask. .........................................................................................87
Chapter 16. Building bridges, and pseudo−bridges with Proxy ARP. .........................................................89
16.1. State of bridging and iptables .......................................................................................................89
16.2. Bridging and shaping. ...................................................................................................................89
16.3. Pseudo−bridges with Proxy−ARP. ...............................................................................................89
16.3.1. ARP & Proxy−ARP ............................................................................................................90
16.3.2. Implementing it. ..................................................................................................................90
Chapter 17. Dynamic routing − OSPF and BGP. ..........................................................................................92
Chapter 18. Other possibilities. .......................................................................................................................93
Chapter 19. Further reading. ...........................................................................................................................95
Chapter 20. Acknowledgements. .....................................................................................................................96
iii
184432247.004.png
Chapter 1. Dedication
This document is dedicated to lots of people, and is my attempt to do something back. To list but a few:
· Alexey N. Kuznetsov
Rusty Russell
· The good folks from Google
· The staff of Casema Internet
·
Chapter 1. Dedication
1

Plik z chomika:

Inne pliki z tego folderu:

Inne foldery tego chomika:

Zgłoś jeśli naruszono regulamin