8
votes
Accepted
Configuring OSPF on two directly connected routers which are in different areas
In order to connect two areas, one router has to serve as an area border router (ABR). That router has interfaces in both areas. In other words, the boundary between two areas is a router, not the ...
- 67.1k
7
votes
How to run a CAM Table Overflow attack in GNS3 using Cisco 3725 routers?
First and foremost, I must indicate that I am mostly active on the IT Security StackExchange website. Since this current website may reach a different public I find it wiser to tell that, while I ...
- 335
7
votes
Accepted
GNS3 switches vs Real switches performance
Do emulated switches perform worst than actual switches?
Yes, of course software performs worse than hardware. Physical switches do their switching in hardware, and are able the get wirespeed ...
- 98.7k
6
votes
Accepted
Should a PC populate its ARP table when a frame is not destined to it?
Yes, this is expected behaviour.
Even though PC3 sees the ARP request from PC1, it does not populate it's ARP cache with the IP-to-MAC mapping of PC1.
While this may not seem to be the most efficient ...
- 9,421
6
votes
Why switch has records in mac-table when i just set ip address to the hosts which connected to the switch?
But when i just set ip address to the two hosts, and i found there are the two hosts mac address in switch! Is this the expected result? I even didn't ping between the two hosts, how the switch ...
- 27.2k
5
votes
Accepted
Carrying remote VLAN via 2 routers to the local gateway
You can use Ether in IP, defined in RFC 3398 to tunnel ethernet through IP, if you equipment supports it. It's similar to the VxLAN approach, but a little simpler and older.
If you don't have those ...
- 16.2k
5
votes
GNS3 Routers - what is the difference beteween line con 0, line aux 0, and line vty 0 4?
Since GNS3 is a replication of the Cisco IOS, the difference is as followed:
line con 0
This is the physical console port on the switch/router in which you can configure/troubleshoot the device.
line ...
- 1,732
4
votes
Accepted
Is "Host unreachable" the same as "Communication administratively prohibited" in Access List ping response?
Practically it's the same. The router isn't silently dropping the packets but returning an ICMP error message 3/13, informing the sender that the packet has been filtered.
Users often don't care why ...
- 82.6k
4
votes
Duplex mismatch between a Fast Ethernet router and Gigabit Ethernet switch with auto negotiation
The message is from CDP duplex mismatch detection - it might indicate a duplex mismatch that isn't there, indicating a problem with CDP itself (esp. in GNS3).
Check each side's interface status (show ...
- 82.6k
4
votes
Difference between various network simulators
There's a fundamental distinction to make first, between a simulator and an emulator.
A simulator is a program that replicate the behavior of the simulated device . It is as faithful to the original ...
- 19.5k
4
votes
Accepted
BGP (RIB-Failure - Higher admin distance)
The rib-failure is telling you the learned BGP route isn't best because there is another route -- in this case, directly connected routes -- with a better Admin Distance (AD). On R1 & R3 there is ...
- 5,449
3
votes
BGP problems, cannot ping
You have not set the clock rate on the DCE side of the connection. The command is clock rate <rate>. See Cisco IOS Interface and Hardware Component Command Reference.
Another problem is that ...
- 98.7k
3
votes
Accepted
Could launching a virtual router with less-than-recommened RAM cause interfaces to not initialize?
I believe officially vSRX needs 4 GB RAM, 2 CPU and a min of 16 GB disk space. If this requirement is not met, an instance can behave abnormally and will be hard to debug. Maybe you are facing a ...
- 66
3
votes
Accepted
Simulate a real L3 WAN with VIRL or GNS3 (+/- VIRL images)
You can simulate the L2 or L3 WAN, but only when it is functioning correctly. You won't be able to effectively simulate problems like signal fade, or unidirectional links. GNS3 and VIRL (and now EVE)...
- 67.1k
3
votes
Configuring OSPF on two directly connected routers which are in different areas
To exchange routes in this topology you don't need two areas.
A two-router setup would be best configured in a single area. Best practice is to configure them both in area 0, but if it's going to ...
- 86
3
votes
Accepted
Virtual devices on GNS3 cannot ping the physical host
Since you can ping PC-1 from the physical PC (PH) but not vice versa, the most logical explanation is that PH doesn't reply to echo requests (firewall, filtering, ...).
Edit after your added PH's ...
- 82.6k
3
votes
Carrying remote VLAN via 2 routers to the local gateway
You can use VxLAN, defined in RFC7348, to span a VLAN onto different sites.
Basically it encapsulates a VLAN into IP.
This off course add some overhead, and your routers at each endpoint need to ...
- 19.5k
3
votes
Accepted
If traceroute fails why does ping still work?
That is because ping uses ICMP Echo Request and ICMP Echo Reply. Your traceroute is using UDP, which uses addresses called ports. Apparently, the port you are using in the traceroute commend is closed ...
- 98.7k
3
votes
Accepted
ipv6: I can ping only 1 interface within same network even with static route
You need to remember that ping is bidirectional. You send out an ICMP echo request, and you hope to get back an ICMP echo reply. That means that the replying device must also have a route back to the ...
- 98.7k
3
votes
Accepted
Juniper vMX Routers can't ping each other in GNS3
I think the interfaces you have connected in GNS3, em2 ---- em2 are actually named ge-0/0/0 by the vMX nodes. Try edit interfaces rename ge-0/0/2 to ge-0/0/0 on both vMX, commit, and check for ...
- 5,449
3
votes
Accepted
Unable to add an abbreviated IPv6 to a Cisco router
You are trying to configure a link-local address without the link-local keyword.
ipv6 address fe80::1 link-local
- 98.7k
3
votes
GNS3 Router Telnet Configuration
You have to distinguish between the simulated network and the control of the simulator. The router is part of the simulation -- its networks are also part of the simulation.
In real life, the console ...
- 67.1k
2
votes
GNS3 ASA not pinging itself
I believe you also have a set a security level for the interfaces in an ASA. From what I remember, there's three things that need to be configured for each interface:
Name
Security Level
IP Address
- 21
2
votes
GNS3 ASA not pinging itself
You need to set the interface name otherwise the interface will remain unreachable.
e.g.
interface gi0
nameif inside
ip address 10.0.0.1 255.255.255.0
no shutdown
To verify your interface status
...
- 767
2
votes
Accepted
Wireshark is giving error message while capturing packets from GNS3?
Check the location of your Wireshark install , make sure it is like
tail.exe -f -c +0b %c | "D:\Wireshark\Wireshark.exe" -k -i - ,for your case.
may you need also to shut down your windows firewall
- 3,444
2
votes
Block ICMP ping from a PC to a PC
First you must deny the packets from host 3 to host 1; then permit any thing else.
access-list 101 deny ip host 192.168.1.51 host 192.168.1.34
access-list 101 permit ip any any
however, if you want ...
- 61
2
votes
Accepted
Is there no "mode on" for channel-group in GNS3?
The problem was existing because I was not using ether switch module ports that is added to router to handle it as switch
- 141
2
votes
Accepted
How to enable DHCP Cisco router
Move to configuration mode by typing this (you exclude address that you don't want the DHCP to assign to any device, e.g. printers, static
IP addresses, etc.):
Router# config t
Router(conf)# ip dhcp ...
- 36
2
votes
Accepted
How to assign multiple VLANS to a port?
I think you're assigning ports the wrong way. You have to specify each port before you enter the vlan command. Something like this:
MainSwitch(config)#interface fastEthernet 1/4
MainSwitch(config-...
- 67.1k
2
votes
Accepted
GNS3 Latency test
You answered your own question. GNS3 emulates routers and switches, so it can't work as fast as dedicated processors. In this case, you have one processor trying to do the work of eight, and emulate ...
- 67.1k
Only top scored, non community-wiki answers of a minimum length are eligible