Question

BGP Advice needed.

Asked by: MarkJenks

Looking for some advise to make sure that this is setup the way it needs to be.

2 Cisco 3825 Routers, 1gb ram each.

3 ISP's (1 - 4.5mb, 1 - 10mb, 1 - 15mb)

Just brought the 3rd ISP online, and am going to take down the 4.5MB when the contract expires.

Traffic is moving in all directions right now just fine.  Inbound is load sharing between the 3825, and with the OSPF shared path, outbound is also sharing.

My concern is that I am getting lots of inconsistent-as entries.  I know that the BGP for the new ISP has only been announced for about 1.5 weeks, but I'm wonder if there is more work to do here.  We are moving our data center behind this connection in a few weeks, so I get time to work though any issues now.

I was wondering if I need to use more route-maps to clean up which traffic goes into which direction.

Any thoughts or concerns?

-Mark

ROUTER1:
 
interface Loopback1
 ip address 2.2.120.253 255.255.255.255
!
interface Null0
 no ip unreachables
!
interface GigabitEthernet0/0
 bandwidth 150000
 ip address 8.8.126.38 255.255.255.252
 ip access-group inbound-acl in
 no ip unreachables
 no ip proxy-arp
 duplex auto
 speed auto
 media-type rj45
!
interface GigabitEthernet0/1
 ip address 2.2.120.2 255.255.255.128
 ip ospf authentication message-digest
 ip ospf message-digest-key 1 md5 xxxxxx
 duplex auto
 speed auto
 media-type rj45
!
router ospf 100
 log-adjacency-changes
 network 2.2.120.0 0.0.0.127 area 2.2.120.0
 default-information originate always
!
router bgp xx497
 no synchronization
 bgp log-neighbor-changes
 bgp dampening
 network 2.2.120.0
 network 2.2.120.0 mask 255.255.255.0
 neighbor 2.2.120.254 remote-as xx497
 neighbor 2.2.120.254 update-source Loopback1
 neighbor 2.2.120.254 next-hop-self
 neighbor 8.8.126.37 remote-as x663
 neighbor 8.8.126.37 soft-reconfiguration inbound
 neighbor 8.8.126.37 prefix-list input-route-filter in
 neighbor 8.8.126.37 prefix-list announce-out out
 no auto-summary
!
ip forward-protocol nd
ip route 2.2.120.0 255.255.255.0 Null0
ip route 2.2.120.0 255.255.255.128 GigabitEthernet0/1
ip route 2.2.120.254 255.255.255.255 2.2.120.1
!
!
ip access-list extended inbound_acl
 remark - Block Efficient Short Remote Operations
 deny   udp any eq 259 any
 deny   udp any any eq 259
 remark - Block SNMP
 deny   udp any any range snmp snmptrap
 deny   tcp any any range 161 162
 remark - Block Cisco SNMP Ports
 deny   udp any any eq 1993
 deny   tcp any any eq 1993
 remark - Block SMUX
 deny   udp any any eq 199
 deny   tcp any any eq 199
 remark - Block SynOptics SNMP Relay Port
 deny   udp any any eq 391
 deny   tcp any any eq 391
 remark - Block AgentX
 deny   tcp any any eq 705
 remark - Filter RFC 1918 Addresses
 deny   ip host 0.0.0.0 any
 deny   ip 10.0.0.0 0.255.255.255 any
 deny   ip 127.0.0.0 0.255.255.255 any
 deny   ip 172.16.0.0 0.15.255.255 any
 deny   ip 192.168.0.0 0.0.255.255 any
 deny   ip 224.0.0.0 0.0.31.255 any
 deny   ip 255.0.0.0 0.255.255.255 any
 remark -  additional addresses
 deny   ip 0.0.0.0 0.255.255.255 any
 deny   ip 169.254.0.0 0.0.255.255 any
 deny   ip 192.0.2.0 0.0.0.255 any
 deny   ip any 224.0.0.0 31.255.255.255
 remark - Anti Spoofing Filter
 deny   ip 2.2.120.0 0.0.0.255 any
 deny   ip host 8.8.126.38 host 8.8.126.38
 remark - Permit IP Addresses Assigned by ISP
 permit ip any 2.2.120.0 0.0.0.255
 remark - Allow traffic to the routers external interface
 permit ip any host 8.8.126.38
 remark -  Block Remaining Traffic
 deny   ip any any
!
!
ip prefix-list AdvertisedNetworks seq 10 permit 2.2.120.0/24
!
ip prefix-list DEFAULT-ONLY seq 100 permit 0.0.0.0/0
!
ip prefix-list announce-out seq 10 permit 2.2.120.0/24 le 32
ip prefix-list announce-out seq 20 deny 0.0.0.0/0 le 32
!
ip prefix-list input-route-filter seq 10 deny 10.0.0.0/8 le 32
ip prefix-list input-route-filter seq 25 deny 127.0.0.0/8 le 32
ip prefix-list input-route-filter seq 40 deny 169.254.0.0/16 le 32
ip prefix-list input-route-filter seq 45 deny 2.2.120.0/24 le 32
ip prefix-list input-route-filter seq 70 deny 192.168.0.0/16 le 32
ip prefix-list input-route-filter seq 85 deny 224.0.0.0/3 le 32
ip prefix-list input-route-filter seq 90 permit 0.0.0.0/0 le 24
ip prefix-list input-route-filter seq 100 permit 0.0.0.0/0
 
 
ROUTER2:
!
interface Loopback1
 ip address 2.2.120.254 255.255.255.255
!
interface Null0
 no ip unreachables
!
interface GigabitEthernet0/0
 bandwidth 100000
 ip address 4.4.33.22 255.255.255.252
 ip access-group inbound_acl in
 no ip unreachables
 no ip proxy-arp
 ip route-cache flow
 load-interval 30
 duplex auto
 speed auto
 media-type rj45
!
interface GigabitEthernet0/1
 ip address 2.2.120.161 255.255.255.240 secondary
 ip address 2.2.120.1 255.255.255.128
 ip route-cache flow
 ip ospf authentication message-digest
 ip ospf message-digest-key 1 md5 7 xxxxx
 load-interval 30
 duplex auto
 speed auto
 media-type rj45
!
interface Serial0/0/0:0
 ip address 3.3.255.218 255.255.255.252
 ip access-group inbound_acl in
 no ip unreachables
 no ip proxy-arp
 encapsulation ppp
 ip route-cache flow
 load-interval 30
!
interface Serial0/0/1:0
 ip address 3.3.255.210 255.255.255.252
 ip access-group inbound_acl in
 no ip unreachables
 no ip proxy-arp
 encapsulation ppp
 ip route-cache flow
 load-interval 30
!
interface Serial0/1/0:0
 ip address 3.3.255.214 255.255.255.252
 ip access-group inbound_acl in
 no ip unreachables
 no ip proxy-arp
 encapsulation ppp
 ip route-cache flow
 load-interval 30
!
router ospf 100
 log-adjacency-changes
 network 2.2.120.0 0.0.0.127 area 2.2.120.0
 default-information originate always
!
router bgp xx497
 no synchronization
 bgp log-neighbor-changes
 bgp dampening
 network 2.2.120.0
 network 2.2.120.0 mask 255.255.255.0
 neighbor 5.5.5.236 remote-as x018
 neighbor 5.5.5.236 ebgp-multihop 2
 neighbor 5.5.5.236 update-source Loopback1
 neighbor 5.5.5.236 soft-reconfiguration inbound
 neighbor 5.5.5.236 prefix-list DEFAULT-ONLY in
 neighbor 5.5.5.236 prefix-list announce-out out
 neighbor 5.5.5.236 route-map Advertised_ISP1 out
 neighbor 4.4.33.21 remote-as x017
 neighbor 4.4.33.21 password 7 xxxxxx
 neighbor 4.4.33.21 soft-reconfiguration inbound
 neighbor 4.4.33.21 prefix-list input-route-filter in
 neighbor 4.4.33.21 prefix-list announce-out out
 neighbor 2.2.120.253 remote-as xx497
 neighbor 2.2.120.253 update-source Loopback1
 neighbor 2.2.120.253 next-hop-self
 no auto-summary
!
ip forward-protocol nd
ip route 5.5.5.236 255.255.255.255 3.3.255.217
ip route 5.5.5.236 255.255.255.255 3.3.255.213
ip route 5.5.5.236 255.255.255.255 3.3.255.209
ip route 2.2.120.0 255.255.255.0 Null0
ip route 2.2.120.0 255.255.255.128 GigabitEthernet0/1
 
ip route 2.2.120.253 255.255.255.255 2.2.120.2
!
 
!
ip access-list extended inbound_acl
 remark - Block Efficient Short Remote Operations
 deny   udp any eq 259 any
 deny   udp any any eq 259
 remark - Block SNMP
 deny   udp any any range snmp snmptrap
 deny   tcp any any range 161 162
 remark - Block Cisco SNMP Ports
 deny   udp any any eq 1993
 deny   tcp any any eq 1993
 remark - Block SMUX
 deny   udp any any eq 199
 deny   tcp any any eq 199
 remark - Block SynOptics SNMP Relay Port
 deny   udp any any eq 391
 deny   tcp any any eq 391
 remark - Block AgentX
 deny   tcp any any eq 705
 remark - Filter RFC 1918 Addresses
 deny   ip host 0.0.0.0 any
 deny   ip 10.0.0.0 0.255.255.255 any
 deny   ip 127.0.0.0 0.255.255.255 any
 deny   ip 172.16.0.0 0.15.255.255 any
 deny   ip 192.168.0.0 0.0.255.255 any
 deny   ip 224.0.0.0 0.0.31.255 any
 deny   ip 255.0.0.0 0.255.255.255 any
 remark -  additional addresses
 deny   ip 0.0.0.0 0.255.255.255 any
 deny   ip 169.254.0.0 0.0.255.255 any
 deny   ip 192.0.2.0 0.0.0.255 any
 deny   ip any 224.0.0.0 31.255.255.255
 remark - Anti Spoofing Filter
 deny   ip 2.2.120.0 0.0.0.255 any
 deny   ip host 4.4.33.22 host 4.4.33.22
 deny   ip host 3.3.255.210 host 3.3.255.210
 deny   ip host 3.3.255.214 host 3.3.255.214
 deny   ip host 3.3.255.218 host 3.3.255.218
 remark - Permit IP Addresses Assigned by ISP
 permit ip any 2.2.120.0 0.0.0.255
 remark - Allow traffic to the routers external interface
 permit ip any host 4.4.33.22
 permit ip any host 3.3.255.210
 permit ip any host 3.3.255.214
 permit ip any host 3.3.255.218
 remark -  Block Remaining Traffic
 deny   ip any any
!
!
ip prefix-list AdvertisedNetworks seq 10 permit 2.2.120.0/24
!
ip prefix-list DEFAULT-ONLY seq 100 permit 0.0.0.0/0
!
ip prefix-list announce-out seq 10 permit 2.2.120.0/24 le 32
ip prefix-list announce-out seq 20 deny 0.0.0.0/0 le 32
!
ip prefix-list input-route-filter seq 10 deny 10.0.0.0/8 le 32
ip prefix-list input-route-filter seq 25 deny 127.0.0.0/8 le 32
ip prefix-list input-route-filter seq 40 deny 169.254.0.0/16 le 32
ip prefix-list input-route-filter seq 45 deny 2.2.120.0/24 le 32
ip prefix-list input-route-filter seq 70 deny 192.168.0.0/16 le 32
ip prefix-list input-route-filter seq 85 deny 224.0.0.0/3 le 32
ip prefix-list input-route-filter seq 90 permit 0.0.0.0/0 le 24
ip prefix-list input-route-filter seq 100 permit 0.0.0.0/0
 
!
route-map Advertised_ISP1 permit 10
 match ip address prefix-list AdvertisedNetworks
 set as-path prepend xx497 xx497 xx497
!
route-map Advertised_ISP2 permit 10
 match ip address prefix-list AdvertisedNetworks

                                  
1:
2:
3:
4:
5:
6:
7:
8:
9:
10:
11:
12:
13:
14:
15:
16:
17:
18:
19:
20:
21:
22:
23:
24:
25:
26:
27:
28:
29:
30:
31:
32:
33:
34:
35:
36:
37:
38:
39:
40:
41:
42:
43:
44:
45:
46:
47:
48:
49:
50:
51:
52:
53:
54:
55:
56:
57:
58:
59:
60:
61:
62:
63:
64:
65:
66:
67:
68:
69:
70:
71:
72:
73:
74:
75:
76:
77:
78:
79:
80:
81:
82:
83:
84:
85:
86:
87:
88:
89:
90:
91:
92:
93:
94:
95:
96:
97:
98:
99:
100:
101:
102:
103:
104:
105:
106:
107:
108:
109:
110:
111:
112:
113:
114:
115:
116:
117:
118:
119:
120:
121:
122:
123:
124:
125:
126:
127:
128:
129:
130:
131:
132:
133:
134:
135:
136:
137:
138:
139:
140:
141:
142:
143:
144:
145:
146:
147:
148:
149:
150:
151:
152:
153:
154:
155:
156:
157:
158:
159:
160:
161:
162:
163:
164:
165:
166:
167:
168:
169:
170:
171:
172:
173:
174:
175:
176:
177:
178:
179:
180:
181:
182:
183:
184:
185:
186:
187:
188:
189:
190:
191:
192:
193:
194:
195:
196:
197:
198:
199:
200:
201:
202:
203:
204:
205:
206:
207:
208:
209:
210:
211:
212:
213:
214:
215:
216:
217:
218:
219:
220:
221:
222:
223:
224:
225:
226:
227:
228:
229:
230:
231:
232:
233:
234:
235:
236:
237:
238:
239:
240:
241:
242:
243:
244:
245:
246:
247:
248:
249:
250:
251:
252:
253:
254:
255:
256:
257:
258:
259:
260:
261:
262:
263:
264:
265:
266:
267:
268:
269:
270:
271:
272:
273:
274:
275:
276:
277:
278:
279:

Select allOpen in new window

This Question has been solved and asker verified All Experts Exchange premium technology solutions are available to subscription members.

Subscribe now for full access to Experts Exchange and get

Instant Access to this Solution

  • Plus...
  • 30 Day FREE access, no risk, no obligation
  • Collaborate with the world's top tech experts
  • Unlimited access to our exclusive solution database
  • Never be left without tech help again

Subscribe Now

Asked On
2009-06-16 at 07:24:33ID24495629
Tags

cisco

,

bgp

,

ios

,

multi-homed

Topics

Network Routers

,

Network Design & Methodology

Participating Experts
1
Points
125
Comments
6

Trusted by hundreds of thousands everyday for fast, accurate and reliable tech support.

  • "The time we save is the biggest benefit of Experts Exchange to Warner Bros. What could take multiple guys 2 hours or more each to find is accessed in around 15 minutes on Experts Exchange." Mike Kapnisakis, Warner Bros.
  • "Our team likes having a resource that is more secure than just using Google and most experts using this service really know their stuff. It's nice to look here first versus using Google." Dayna Sellner, Lockheed Martin
  • "Anytime that I've been stumped with a problem, 9 out of 10 times Experts Exchange has either the accepted solution or an open discussion of the potential solution to the problem." Kenny Red, eBay Inc.

See what Experts Exchange can do for you.

Got a question?

We've got the answer.

Experts Exchange has been collecting answers to technology questions since 1996…3 million and counting! If you have a question, chances are we already have your answer.

Screenshot of Experts Exchange Knowledgebase

Need individual assistance?

Our experts are ready to help.

If you can't find the exact answer you're looking for, ask our exclusive community of 50,000 experts. You’ll get a personalized answer from a trusted professional.

Screenshot of Experts Exchange Knowledgebase

Want to learn from the best?

Read articles from industry experts.

Thousands of free tech tips, tricks, how-to’s and tutorials are available in our peer reviewed articles section. See for yourself how smart our experts are, no login required.

Screenshot of an Article

Working on a long term project?

Store your work and research.

Save solutions to your questions, answers you’ve discovered through searching plus helpful articles in your personal knowledgebase for easy future access.

Screenshot of Experts Exchange Knowledgebase

Access the answers to your technology questions today.

Subscribe Now

30-day free trial. Register in 60 seconds.

What Makes Experts Exchange Unique?

Members of the expert community talk about why the experience at Experts Exchange is different than what you will find anywhere else.

Trusted by the world's most respected brands.

image of each brand's logo

Faithfully serving IT professionals since 1996.

Experts Exchange Logo

Try it out and discover for yourself.

Subscribe Now

30-day free trial. Register in 60 seconds.

Related Solutions

  1. BGP
    Here is a nice large question for routing experts out there (I specifically have jlevie in mind). Basically, I neeed someone to explain, with examples and perhaps weblinks, the BGP routing protocol. Information that would be useful would be : (0) What is BGP and how does it...
  2. BGP Config
    Hi, I have a question about the config below: router bgp 65535 no synchronization bgp log-neighbor-changes network 192.168.28.0 mask 255.255.252.0 redistribute connected neighbor 10.255.255.5 remote-as 28685 neighbor 10.255.255.5 description RoutIT-primair neighbor ...
  3. BGP performance on Cisco 2610
    We currently have over 20 remote offices using MPLS T1 on Cisco 2610 routers. We use static routing. I am considering converting to BGP but am wondering if the 2610's have sufficient processing power to handle BGP and how 2610's would affect convergence time and overall per...
  4. BGP
    Im configuring a full mesh with 5 routers & 2 switches, but my last router which is a 2600 with version: Version 12.4(1a) & flash:c2600-advsecurityk9-mz.124-1a. but shows below that bgp is none existent, but BGP is in the list, why cant i configure it ? Sanjose2(c...

Free Tech Articles

  1. WARNING: 5 Reasons why you should NEVER fix a computer for free.
    It is in our nature to love the puzzle. We are obsessed. The lot of us. We love puzzles. We love the challenge. We thrive on finding the answer. We hate disarray. It bothers us deep in our soul. W...
  2. SCCM OSD Basic troubleshooting
    SCCM 2007 OSD is a fantastic way to deploy operating systems, however, like most things SCCM issues can sometimes be difficult to resolve due to the sheer volume of logs to sift through and the dispe...
  3. Migrate Small Business Server 2003 to Exchange 2010 and Windows 2008 R2
    This guide is intended to provide step by step instructions on how to migrate from Small Business Server 2003 to Windows 2008 R2 with Exchange 2010. For this migration to work you will need the fo...
  4. Create a Win7 Gadget
    This article shows you how to create a simple "Gadget" -- a sort of mini-application supported by Windows 7 and Vista. Gadgets can be dropped anywhere on the desktop to provide instant information, ...
  5. Outlook continually prompting for username and password
    There have been a lot of questions recently regarding Outlook prompting for a username and password whilst using Exchange 2007. There are a few reasons why this would happen and I will try to cover t...
  6. Backup Exchange 2010 Information Store using Windows Backup
    There seems to be quite a lot of confusion around the ability to backup Exchange 2010 using the built in Windows Backup feature. This stems from the omission of this feature prior to Exchange 2007 s...

Cloud Class Webinars

  1. Avoiding Bugs in Microsoft Access
    Alison Balter takes and in-depth look at avoiding bugs in Access. In this webinar you will learn about using the immediate window to debug your applications, invoking the debugger, using breakpoints to troubleshoot, stepping through code, setting the next statement to execute, ...
  2. Top 10 Best New Features in Visio 2010
    Scott Helmers gives live demonstrations of the top 10 new features in Visio 2010. This webinar will teach you how to create compelling diagrams by adding shapes to the page with a single click, linking the shapes in a diagram to data in Excel (or SQL Server, or SharePoint), ...
  3. IT Consultant Business Secrets Revealed
    Michael Munger, Experts Exchange tech pro and IT consultant, pulls back the curtain on his very successful businesses and answers question on every IT consultant and business owner should know about. He shares secrets on what he did to solve the 5 most common problems in IT, ...
  4. Disaster Recovery and Business Continuity
    Quest CTO, Mike Billon, gives an overview of the steps involved in building a dunamic disaster recovery plan. Through case studies and an examination of software/hardware tooles for monitoring and testing, you'll gain a better understandin of where you are, where you want ...
  5. Organize Your Visio Diagrams with Containers and Lists
    Scott Helmers uses cross functional flowcharts, wireframe diagrams, data graphic legends and seating charts to teach you: how to ustilize all three new structured diagram components in Visio 2010, the best practices for organizeing shapes in previous version of Visio, how to organize ...
  6. How to Us Objects, Properties, Events and Methods in Microsoft Access
    Alison Dalter gives an in-depbth look at objects, properties, events and methods in Microsoft Access. In this webinar you will learn about using the object browser, referring to objects, working with properties and methods, working with object variables, understanding the ...

Join the Community

Give a Little. Get a Lot.

Join the community of experts here and help other tech pros by answering question in your area of expertise. You can earn FREE access to all Experts Exchange's premium features and resources.

Join the Community

Answers

 

by: mikebernhardtPosted on 2009-06-16 at 09:27:56ID: 24639629

Can you please clarify what you mean by "My concern is that I am getting lots of inconsistent-as entries?"

 

by: mikebernhardtPosted on 2009-06-16 at 10:06:49ID: 24640012

Here is what it looks like you are doing:
1. You have no route maps on router 1, so other than prefix-list filtering all routes are accepted and sent unchanged. You are sending your ISP all of your 2.2.120 nets no matter the mask.
2. On router 2, you have a route map doing as-prepend to ISP1, which should make that path less preferable for inbound traffic. I am assuming that this is the link you plan to take down? The route map for ISP2 is not being used. Instead, you are sending them all of your 2.2.120 nets no matter the mask.

One question I have is regarding what you're sending out. Are your ISPs accepting the little nets you may be advertising? It would be better to send all ISPs one net as an aggregate of your address space. Most ISPs won't accept a mask greater than 24 bits. This might be the source of the problems you're seeing, I don't know.

 

by: MarkJenksPosted on 2009-06-16 at 10:29:03ID: 24640247

They are both accepting my entire /24.

I am seeing pages and pages of these..  Is that normal, and I'm overreacting?

sh ip bgp inconsistent-as


   Network          Next Hop            Metric LocPrf Weight Path
* i41.223.232.0/22  74.87.120.254            0    100      0 7017 11955 3356 223          51 25543 i
*>                  206.40.126.37                          0 3663 7018 3320 1249          1 37008 i
*  59.189.0.0/16    206.40.126.37                          0 3663 7018 1239 3886          1 38861 38861 i
*>i                 74.87.120.254            0    100      0 7017 11955 7843 465          7 10091 i
*  59.189.72.0/21   206.40.126.37                          0 3663 7018 1239 3886          1 38861 38861 i
*>i                 74.87.120.254            0    100      0 7017 11955 7843 388          61 10091 i
*  59.189.216.0/21  206.40.126.37                          0 3663 7018 1239 3886          1 38861 38861 i
*>i                 74.87.120.254            0    100      0 7017 11955 7843 388          61 10091 i
*  59.189.232.0/21  206.40.126.37                          0 3663 7018 1239 3886          1 38861 38861 i
   Network          Next Hop            Metric LocPrf Weight Path
*>i                 74.87.120.254            0    100      0 7017 11955 7843 38861 10091 i
*  59.189.240.0/21  206.40.126.37                          0 3663 7018 1239 38861 38861 38861 i
*>i                 74.87.120.254            0    100      0 7017 11955 7843 38861 10091 i
*  59.189.248.0/21  206.40.126.37                          0 3663 7018 1239 38861 38861 38861 i
*>i                 74.87.120.254            0    100      0 7017 11955 7843 38861 10091 i
*  69.26.233.0/24   206.40.126.37                          0 3663 3549 12989 11588 18990 ?
*>i                 74.87.120.254            0    100      0 7017 11955 3356 1239 31892 i
*> 116.212.96.0/24  206.40.126.37                          0 3663 3549 4761 4761 38501 i
* i                 74.87.120.254            0    100      0 7017 11955 7843 6453 18059 i
*> 190.56.128.0/17  206.40.126.37                          0 3663 7018 23520 14754 6458 i
* i                 74.87.120.254            0    100      0 7017 11955 3356 8151 14754 i
*> 192.203.206.0    206.40.126.37                          0 3663 7018 2914 18530 i
* i                 74.87.120.254            0    100      0 7017 11955 3356 23504 i
*> 198.32.68.0      206.40.126.37                          0 3663 7018 2914 8513 i
* i                 74.87.120.254            0    100      0 7017 11955 3356 22351 i
*> 199.184.188.0    206.40.126.37                          0 3663 7018 10439 6130 i
* i                 74.87.120.254            0    100      0 7017 11955 3356 10439 i
*> 202.21.208.0     206.40.126.37                          0 3663 7018 10026 2706 2706 i
* i                 74.87.120.254            0    100      0 7017 11955 7843 4134 4847 i
*> 202.155.108.0/23 206.40.126.37                          0 3663 7018 3561 7473 4761 4761 4761 4795 ?

 

by: mikebernhardtPosted on 2009-06-16 at 10:45:26ID: 24640412

Well, you're receiving the entire internet route table so that is normal. But it's highly unlikely that you need it. You should be able to get by with just the default route. ISPs usually offer options for what they send you:
1. Default only
2. Default plus everything they themselves own
3. Everything

#1 is obviously the simplest option. Since you're load balancing via OSPF, you will still load balance over the default route.
#2 is good if it matters to you to take the most efficient path to your ISP's routes. This way you don't use ISP2 for a route that's connected directly to ISP1.
#3 is good if you need to know where everything is, or if you have other offices connected to one ISP or the other. Even if you use this option, you can, and should, use an inbound route map to control what you install i.e. default plus the specific routes you need. The whole table is an enormous memory hog with no benefit if you're not an ISP yourself.

Your current inbound route map doesn't really do anything because you are denying routes that an ISP will never send you like RFC 1918 and the other stuff, then permitting everything else.Talk to your ISPs about what options they have for route control and they can help you do the required setup with BGP communities or whatever.

Otherwise, just modify your inbound route map to dump what you don't need.

 

by: MarkJenksPosted on 2009-06-16 at 11:02:02ID: 24640563

So, giving that I am accepting everything and have routers can that handle it, you really would not change anything?

I am moving our data center to this location in a few weeks, and giving how much traffic we are expecting, I believe that the full tables would be the best.

 

by: mikebernhardtPosted on 2009-06-16 at 14:28:19ID: 24642793

It seems to me that everything is OK. I still don't know what you meant by inconsistent-as entries. But I also don't see the benefit to you of accepting the entire route table. this best for ISPs, universities, etc. that have connections to lots of other ISPs. you simply want to load share, and advertising the default route from both would accomplish that for you. It doesn't matter how much traffic you're expecting, what matters is how much routing flexibility you need. You have 2 equal paths out.

My experience over the years has been that giving routers more information than they need is not generally a good idea. Maybe a good experiment would be to keep receiving your current routes, but change your prefix list so that you only accept the default route. Monitor your links and see if you are load balancing outbound. If you're meeting that goal, leave it. If not, allow more routes in and see if it changes. I think you'll find that default only is plenty sufficient. But obviously the decision is yours to make.

20120131-EE-VQP-002

3 Ways to Join

30-Day Free Trial

The Experts

98% positive feedback on 31,087 answers since March 2000. angeliii is a Microsoft Most Valuable Professional for his work with MS SQL Server & Develoment.

He has also proven his knowledge of Visual Basic Programming, PHP Scripting and Oracle Databases.

The Experts

97% positive feedback on 10,752 answers since July 2000. lrmoore has more than 18 years experience in the networking industry.

The six-time Mircosoft MVPs specialties include firewalls, virtual private networking, and network management.

Testimonials

"...and excellent source for support... Kind of like having your very own IT dept." Electriciansnet

Testimonials

"I was apprehensive at signing up at first. However... it has already made my life as an IT administrator much easier." JaCrews

Testimonials

"WOW! You guys have great, active, and knowledgeable people on here." moore50

Business Clients

Business Clients

In the Press

"If you’ve got a question... Experts Exchange can supply an answer.”

In the Press

"...an invaluable aid for both IT professionals and those who require tech support."

In the Press

"where IT professionals provide quick answers on just about any topic"

Business Account Plans

Loading Advertisement...