A tag for discussion of "routing", the process of selecting which network path to send traffic to.
2
votes
3answers
87 views
Reconfiguring Layer3 Switch to enable IP routing and become the default gateway
Current configuration with HP Procurve 2848 switch at a colocation facility consists of using the ISP switchport as the default gateway. The current configuration is very basic with only 1 vlan assign ...
3
votes
6answers
263 views
Can the same network IPs be used more than once
Because of how routers separate networks is it possible to say use the network 192.168.1.0/24 several times as long as you have enough networks to separate?
Example:
192.168.1.0/24 <--> ...
0
votes
0answers
25 views
Wireless router connecting to various routers to wired [closed]
Overview:
I have a central wireless N hidden network for my house. Some of my products (computers, irrigation, cameras) would be so much easier if I could connect as a wired device. What I would ...
-1
votes
1answer
102 views
Static routing in Linux
I want to know how static routes are evaluated in Linux. Have a few more specific questions.
How are the metrics used?
If the packet is at the last hop what do I put in the next hop field of the ...
5
votes
2answers
92 views
OSPF Stuck in Exstart Adjacency State
According to this article two routers will get stuck in the exstart adjacency state when their configured MTU sizes do not match. Does a VLAN tag affect this as well even if the routers involved are ...
1
vote
1answer
120 views
Routing Serial cables instead of Ethernet
I am doing some CCNA training videos and using packet tracer and they showed using a serial cable to connect two routers. Why are serial cables used instead of Ethernet cables? Does it depend on the ...
3
votes
3answers
147 views
How do apps know about asymmetric routing?
We made did a campus LAN upgrade recently, during which we migrated from a mixed EIGRP/OSPF IGP to a multi-area OSPF redistributing to/from BGP on our WAN. We have two entry points on different sides ...
1
vote
2answers
101 views
loopback ip issue
So I have a weird issue. If I configure a /30 ip on an ethernet interface, for example 10.10.10.1/30 on Router1 and 10.10.10.2/30 on an ethernet interface on Router2, I can ping each other fine...no ...
2
votes
1answer
106 views
ASA Transparent Mode Route Lookup
In what situations will an ASA perform route lookup? (transparent mode)
3
votes
1answer
131 views
Windows 8 Pro not respecting longest prefix match
So, first of all, why I post a Windows networking question here:
http://serverfault.com/questions/390332/windows-equivalent-for-ip-route-show-cache
...
-1
votes
2answers
101 views
How to keep office LAN private from public WLAN
I handle the network at a small business; it's not my primary job but one that I am in charge of. My boss owns a house next to the office that he uses as a general meeting area and as a guest house ...
11
votes
2answers
229 views
BGP multipath with different ASNs feasible for production networks?
on Cisco (this command is hidden for some reason)
#bgp bestpath as-path multipath-relax
The default BGP behavior only installs only routes with exact the same AS_PATH into RIB. With ...
5
votes
3answers
136 views
/23 PI space - breakup
a client currently has a /23 PI space where the route-object is currently managed by ISP-A
we want to split the PI space into two /24's but not certain on how best to go about this.
ISP-A will use ...
8
votes
3answers
508 views
Do today's routers prevent fake IP headers?
I know people can modify the IP headers and change source IP address, but it should be simple for network devices to detect those messages. If they don't, why is it so hard? Does it add too much ...
11
votes
6answers
324 views
What happens when the ARP cache overflows?
In at least one implementation there is a hard limit on the capacity of the ARP table. What happens when the ARP cache is full and a packet is offered with a destination (or next-hop) that isn't ...
15
votes
3answers
666 views
How to check for a valid public IP address?
Consider a list of IP addresses as provided by the X-Forwarded-For HTTP header:
10.0.0.142 , 192.168.0.10 , 212.43.234.12 , 54.23.66.43
I would like to know which is the first ...
5
votes
1answer
129 views
traffic engineering - policies for BGP vs static routes
Considering a transition of specific public Internet site via a new location. At the current location, I've got a static route configured in my Cisco router pointed to my internal firewall. The new ...
0
votes
1answer
78 views
connect two routers [closed]
I have two routers. One main which is connected to ISP with optical cable, and second which is connected to the first one, with ethernet cable.
The second router have private ip address and everything ...
6
votes
3answers
230 views
interpreting ping results
I'm pinging yahoo.com and am I'm puzzled by the result.
C:\Users\jon>ping -t yahoo.com
Pinging yahoo.com [98.138.253.109] with 32 bytes of data:
Reply from 98.138.253.109: bytes=32 time=195ms ...
2
votes
1answer
85 views
Portforwarding by Subdomain
I want to have multiple servers behind a single firewall and access each with a different subdomain.
Currently, I am having to have each server tied to a different port (which my firewall forwards to ...
8
votes
2answers
116 views
Can one configure several static EIGRP Neighbors on one interface?
Can one configure several static EIGRP Neighbors on one interface and are there any considerations apart from disabling split-horizon that one should consider?
7
votes
4answers
153 views
Asymetric routing - causes and effects?
It happens that I run across customers who have what I define as an "asymetric routing" in their networks. Simply said, they have two gateways on the same IP subnet. The clients are configured to ...
4
votes
4answers
215 views
How risky is a personal-use-only wireless subnet inside the corporate subnet?
My company's security policy with respect to wireless routers is to not use them at all -- everyone's wired in. Devices for personal use, such as laptops or cell phones, have to use their phone's data ...
0
votes
2answers
127 views
Weird TCP ports open on remote host, Apple Airport Extreme, my network only [closed]
I'm getting strange results for open ports on internet hosts on my network. I suspect some kind of weird router behavior, but I can't really figure out what it is.
NMAP from my workstation (on my ...
5
votes
1answer
74 views
Why there is a maximum of 4096 queues in WFQ?
In QoS there is a variety of Queuing methods and one of them is WFQ, which organizes the flows in different queues where each queue has a weight that determines which flow will go first.
Now for ...
6
votes
1answer
157 views
BGP remote-triggered blackhole (RTBH) filter for Juniper
I'm trying to find the most elegant way to implement a RTBH filter for routes received from a customer.
The filter should:
Only accept the customers own prefixes from a prefix-list
Only accept /32 ...
3
votes
1answer
123 views
Routing table in QNX
I've an embedded system running on QNX 6.2.1. (I'll call it QNX box.) The QNX box has two network adaptors. I've configured the driver, so they appear as en0 and en1. Here are their IP settings:
...
6
votes
2answers
114 views
Reliable connectivity to China
I have been struggling on getting reliable connectivity to China (AS4837 China Unicom Backbone, AS4134 China Telecom Backbone, AS4538 China Education and Research Network Center)
On most links I have ...
5
votes
3answers
223 views
Inbound BGP load-balancing from same ISP router
I have two BGP routers for DIA with an issue with one provider in that the two links to this provider land on the same SP router. My ethernet handoffs via two separate MetroE links from another ...
2
votes
1answer
111 views
Isolating Juniper Management Plane
Out of the box, it seems that the Juniper management routing is part of the default route table. Can I use logical systems to isolate the service plane from management routing? Are there any ...
2
votes
2answers
77 views
Setting the same gateway address at a DR site as our main site
I have a question about routed traffic across a site to site VPN between 2 Cisco ASA 5510's. We have our office side and our DR side and the question is could I have an IP conflict of gateway IP ...
4
votes
4answers
161 views
USA proxy IP in a box [closed]
My boss, US expat, is requesting a solution to watch his US TV shows and other content while he is staying here (small European country you probably never heard of). As I think, the ideal solution ...
10
votes
2answers
354 views
RIP routing is broken between two routers
There are 2 routers connected something like this:
Network1 ----- (172.16.1.1/24) Router 1 (172.16.3.1/30) ------ (172.16.3.2/30) Router 2 ------ (172.16.2.1/24) Network 2
I try to add addresses ...
12
votes
3answers
320 views
CEF operations on L3 switch vs router
I understand that L3 switches use CEF for faster packet forwarding. However, CEF will not work for packets that need to undergo NAT. Does this mean CEF isn't used by edge routers and edge L3 switches? ...
9
votes
3answers
201 views
Circular BGP propagation
This one is a difficult to describe, it's hypothetical because I'm learning about routing and right now I'm focused on BGP.
Let's say my ASN is 65000, and I announce 192.0.2.0/24. My peer, AS 65001 ...
7
votes
3answers
136 views
Default-network and default-gateway
When would you choose to use the ip default-network command instead of the ip default-gateway command?
6
votes
1answer
190 views
What factors drive L2 vs L3 in the access layer?
When designing an access layer, best practices today seem to indicate going toward a L3 design. I know the answers may be different depending on whether or not we talking about a DC design or ...
2
votes
2answers
88 views
Is migrating to VRF or rolling-back an easy proposition?
If VRF is implemented for routing table separation such as having an overlay network for a guest network that doesn't mix with regular LAN routing, is migrating to it easily done on Cisco switches ...
3
votes
6answers
106 views
What are the reasons for choosing separate or combined VPN and Internet routers?
Here's a network design question: I've just been reading "IPv6 for Enterprise Networks" by McFarland et. al. and it (among other Cisco documents) separates out Internet routing from remote access VPN. ...
5
votes
3answers
53 views
How to apply configuration after replacing Routing Engine(RE) for CISCO7609-S?
Senario:
I have the backup configuration file. But I don't any USB drive or compact flash card. After replacing the Routing Engine, I tried to copy/paste the configs (around 12k lines) from the ...
11
votes
1answer
284 views
What is the difference between a VRF and GRF? (cisco)
I've heard about VRF's and GRF's, but was is the difference between those 2? (cisco)
2
votes
7answers
409 views
Dynamic Routing Protocol (IGP) over IPSec VPN tunnels to branch offices?
What are the best practices for running an IGP to learn networks at HQ from branch offices when those offices connect via IPSec LAN-to-LAN VPN tunnels over the Internet? The branch offices terminate ...
3
votes
2answers
221 views
Adding static routes with metrics in Windows7
I have been trying to add a static route in my windows machine as follows:
C:\Windows\system32>route ADD 10.0.0.25 10.10.10.3 metric 1
OK!
But when I checked the routing table, the metrics of ...
8
votes
6answers
504 views
Best practice for dual-homing site with two ISPs?
I am subscribed to two ISPs, a fast expensive one and a cheap but slower one. They use different technologies, cable and ADSL, so there isn't much of a single point of failure, and all my comms ...
6
votes
1answer
136 views
Remote Campus Routing Design
A third party provider supplies connectivity my remote satellite campus over metro ethernet. Due to red tape the provider is required to supply a routed point-to-point connection (R2 and R3) to the ...
7
votes
3answers
271 views
Cisco: prevent vlan's of communicating with eachother on cisco router (ACL alternative)
Setup: Cisco router with multiple VLAN's configured on it.
How can you prevent 2 VLAN's communicating with eachother? Normally I would do this with ACL's like this:
access-list 102 deny ip 1.1.1.0 ...
4
votes
2answers
128 views
VPN routing for hosts with multiple ip addresses
I use Mikrotik RouterOS as the NAT router. Some hosts behind the router also have a direct connection to the Internet and these hosts have a default route to the ISP's gateway instead of RouterOS.
I ...
8
votes
2answers
208 views
What are the differences between VRRP and HSRP?
Is there any significant difference between VRRP and HSRP?
7
votes
4answers
324 views
Difference between access list and prefix list?
Can someone explain with an example whats the difference between an access list and prefix list.
6
votes
3answers
204 views
BGP - Soft Reset Outbound & Verification
My understanding of the command:
clear ip bgp * soft out
is that the router on which the command is issued will re-advertise everything it knows about BGP to it's neighbors. As I see it, it's as if ...
