Friday, October 21, 2011

Common Questions & Guides for Cisco 1841 from Yahoo Answers


As we known, Cisco 1841 series is a super star among Cisco 1800 series,
Q: How to configure Cisco 1841 router to connect through satellite?
I am trying to configure my Cisco 1841 router to connect to the Internet through a satellite dish. I am stuck. All i need to know is what to do on my router. Sample config would be appreciated as well. I also want the outside world to access services such as web and ftp through the satellite connection
The connection is as follows
LAN----------|Cisco 1841 Router|-----------|Satellite modem|------Internet
A: Have you used another router in the past and you're just upgrading to the new Cisco one? If so, just copy the settings from the old router. If this is a new install, you're going to need the info from your satellite internet provider, like your login info. Your IP address if you have one (as opposed to DHCP), etc.

Q: Can I display a Cisco 1841 system info on my PC?
I am new to cisco equipments, I have a Cisco 1841. First is it possible to display a the router info on my PC. If so how do i connect the 1841 to my PC. And also can configure the router from my PC like the Linksys routers.
A: The Cisco routers are a professional grade router and way outperform the low end home grade routers like Linksys.
The Cisco 1841 can be configured using CLI (command line interface) with a serial connection and Hyperterminal on a Windows computer. It can also be configured using CLI using the LAN port of your pc connected to its LAN port.
Later models of 1841 also permit configuration via a Web GUI interface. (You are familiar with Web GUI as it is the only promulgated mode for configurations on low end routers.)
We do not know which version of firmware you have on your 1841 so we cannot tell you whether it supports the Web GUI mode or not. You indicate you are new to Cisco equipment but you did not indicate this was a new Cisco 1841.
The best way to determine this is to try to log onto it. You will need the user name and password. If these are lost, you can do a factory reset and use factory defaults.

Q: How can we use 3 ADSL line in Cisco Router 1841?
I have Cisco 1841 router. I already installed 2 ADSL WIC in both slot available on it. I want install one more ADSL WIC too in this router (3rd one)
Please let me know any way to adopt 3 rd WIC card on it ?. If not, please let me know , Is it available 2port ADSL WIC ?
A: Cisco doesn't make a 2 line ADSL WIC. You have 2 options:
1. Pull at least one of the WIC-1ADSL cards and install a WIC-4ESW 4-port switch and use external DSL modems.
2. Upgrade to a Cisco 28xx series router that supports more expansion cards.

Q: I would like to add more ether net ports to cisco 1841, which card i must use?
A: If you want to use these Ethernet ports as routed ports like build-in Ethernet ports, You have two options listed below:
HWIC-1FE 1-port 10/100 Routed Port HWIC
HWIC-2FE HWIC two routed port
If you are going to connect some PC or other devices, you can use switch ports like below:
HWIC-4ESW Four port 10/100 Ethernet switch interface card
You have only two slot in this router so choose carefully.

Q: How to enable bgp in cisco 1841 router?
A: You need advanced IP Services software image for this. See sources link [1] for further details, on how to upgrade.
See link [2] for configuration guide on BGP.
the quick answer is :
1.router bgp autonomous-system
2. network network-number [mask network-mask] [route-map route-map-name].
Configuring a good BGP router is not an easy task. You should read more about this, if you want to use it in a real-life network implementation.

Q: Cisco 1841 - how to NOT route between subnets?
I have an 1841 router connected to the Internet connection via one ethernet interface and half a dozen subnets via a trunk on the other interface. I want each of those subnets to be able to access the internet, but for security reasons I want to prohibit any routing between the subnets so they remain isolated from each other. How would I go about arranging this?
A: Have you made an ACL? Create one to block the subnet you do not want accessed and apply it inbound on the virtual interface.
If I remember right, something like this (i'll use 192.168.1.0/24 as the destination vlan).
access-list 101 deny ip any 192.168.1.0 255.255.255.0
Apply this inbound on the virtual int for this vlan,
virtual int 0/1
access-group 101 in

Q: Example config cisco 1841 with 2 hwic 4esw card using no vlans?
I have a cisco 1841 with 2 hwic 4esw cards and I want to setup the cards to work as L2 switches attached to the FE0/1 interface with the FE0/0 interface used as the connection out. All traffic thru the 2 switches would be NATed through FE0/0 also. Any ideas how I can do this without VLANs
A: How exactly are those two cards connecting to the Fa0/1 interface? You only mention the one router.
To NAT directly on that 1841 for switch ports on those cards, best way is to create an SVI and configure it as nat inside. That would technically require a vlan, but if it's dot1q tags you're trying to avoid you could always make it the native vlan or just the vlan 1 default. Those ports on the two hwics should be access ports anyway so it shouldn't be sending any tagged frames anyway unless you're trunking to something else that you haven't mentioned.
To give you a config I'd need to know what you mean by "I want to setup the cards to work as L2 switches attached to the FE0/1 interface". How are these cards attaching to the Fe (Fa?) interface of the router? You mean "attached" as in they're both part of the same physical router?

Q: How to configure ACL 115 on Cisco 1841?
Host 10.1.10.5 is not allowed to access host 10.1.50.7. All other hosts are allowed to access 10.1.50.7. Configure the ACL on B1 using ACL number 115. Please help!
A: Since I don't know which router is B1 incoming or outgoing traffic the ACL could be written for outgoing.
access-list 115 deny ip host 10.1.10.5 host 10.1.50.7
access-list 115 permit ip host 10.1.10.5 any
for outgoing traffic... would still need ip access-group 115 out on the interface.
alternately it could be written:
ip access-list extended 115
10 deny ip host 10.1.10.5 host 10.1.50.7
20 permit ip host 10.1.10.5 any
Source(s):
This one is a bit easier since your able to place the ACL nearest the point of origin on B1 and you can use an extended.
So the ACL is extended.
Applied to interface FA0/0 on the B1 router.
ACL should be applied to out.
access-list 115 deny ip host 10.1.10.5 host 10.1.50.7
access-list 115 permit ip any any
ip access-group 115 out


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