A basic Router
configuration.
http://www.w3schools.com/html/html_links.asp
A basic Router configuration with references to the commands.
- version 99.9
- service timestamps debug uptime
- service timestamps log uptime
- service password-encryption
- no service udp-small-servers
- no service tcp-small-servers
- !
- hostname FAKE
- !
- !
- ip subnet-zero
- ip domain-name fake.com
- ip name-server 170.30.18.7
- ipx routing 0000.0000.db7c
- clock timezone est -5
- clock summer-time edt recurring
- !
- interface Ethernet0
- description LAN connection to FAKE
- ip address 170.30.34.254 255.255.255.0
- ip access-group 101 in
- no ip redirects
- no ip directed-broadcast
- no ip route-cache
- ip ospf priority 5
- no ip mroute-cache
- lat enabled
- ipx network 1703034
- no mop enabled
- bridge-group 1
- !
- interface Ethernet1
- no ip address
- no ip directed-broadcast
- shutdown
- !
- interface Serial0
- description CONNECTION TO FAKE PLACE
- ip address 170.30.3.202 255.255.255.252
- ip access-group 101 in
- no ip redirects
- no ip directed-broadcast
- no ip route-cache
- ip ospf priority 0
- no ip mroute-cache
- lat enabled
- no fair-queue
- mop enabled
- bridge-group 1
- !
- interface Serial1
- no ip address
- no ip directed-broadcast
- shutdown
- !
- router ospf 37
- network 170.30.34.0 0.0.0.255 area 170.30.34.0
- network 170.30.3.200 0.0.0.3 area 170.30.34.0
- !
- no ip classless
- no logging console
- logging trap debugging
- logging 170.30.18.9
- access-list 101 deny 53 any any
- access-list 101 deny 55 any any
- access-list 101 deny 77 any any
- access-list 101 deny 103 any any
- access-list 101 deny ip host 0.0.0.0 any
- access-list 101 deny ip 127.0.0.0 0.255.255.255 any
- access-list 101 deny ip 192.0.2.0 0.0.0.255 any
- access-list 101 deny ip 224.0.0.0 0.15.255.255 any
- access-list 101 deny ip 10.0.0.0 0.255.255.255 any
- access-list 101 deny ip 192.168.0.0 0.0.255.255 any
- access-list 101 permit ip any any
- !
- !
- !
- !
- snmp-server community private
- snmp-server community public
- snmp-server host 170.30.18.7 public
- bridge 1 protocol dec
- !
- line con 0
- line aux 0
- line vty 0 4
- !
- ntp clock-period 17180635
- ntp server 192.43.244.18 prefer
- end
http://cio.cisco.com/warp/public/707/3.html#app
If the udp-small-servers command is enabled, a Cisco IOSŪ software
device may reply to malformed udp echo packets with some of the contents stored
in a router's memory. By repeatedly sending malformed udp echo packets and
capturing the replies, an attacker can obtain portions of the data that is
stored in a router's memory.
!
Line space on the configuration
Has no effect
on the configuration.
hostname
The name of the Router.
Seen by others
as they log into the router. Useful to determine which router you are currently
in.
ip subnet-zero
Allows the use of the first network, after subnetting is
created, to be used.
http://www.cisco.com/warp/public/105/40.html
Rfc 950
ip domain-name fake.com
Default domain name used to complete unqualified host
names.
Any IP host
name that does not contain a domain name (that is, any name without a dot) will
have the dot and fake.com appended to it before being added to the host table.
Has no effect
on hosts or other devices.
clock timezone est -5
The time zone that is used for the router.
This command
enables the router to be able to interpret the UTC
time from a Time
server and adjust it to the Local Time.
You set the
date to change times.
interface Ethernet0
Placeholder for showing the first Ethernet port.
May also be
Ethernet 0/0 for the first Eth port in the first slot. or FastEthernet 0/0
Labeling all
ports and the Router makes troubleshooting easier. If for example you have
several providers for T1 lines, ISDN or Frame-Relay this would be a good place
to put names, contact numbers or circuit numbers.
Followed by the
subnet mask.
ip access-group 101 in
Application of the rule specified later and direction of
traffic
in which the rule will take effect.
no ip redirects
??? Prevents a packet from being accepted into port X and
being routed out port X ???
no ip directed-broadcast
Prevents the ability to ping the Network address.
By spoofing a legitimate
ip address on a network and pinging the network address you can have the replies
of every host on that network go to the spoofed host and killing its network
bandwidth.
The Local Area
Transport (LAT) protocol is designed to handle multiplexed terminal traffic
to/from timesharing hosts. This protocol is bridged. http://www.cisco.com/warp/public/535/5.html
no mop enabled
Disallows DEC's Maintenance Operations Protocol
http://www.cisco.com/warp/public/535/5.html
bridge-group 1
The bridging component for LAT and MOP.
interface Ethernet1
Placeholder for showing the second Ethernet port.
no ip address
This interface doesn't have an ip address associated with
it.
shutdown
This interface is administratively shut down.
Even with a ip
address associated with it, this interface will not pass traffic until the no
shutdown command is issued for this interface.
interface Serial0
Placeholder for showing the First Serial port.
router ospf 37
Area number for the OSPF routing protocol.
OSPF
Open Shortest Path First
Where snmp
traps should be sent.
line aux 0
Auxiliary port. Physical port on router.
line vty 0 4
Virtual Terminal line for Telnet.
ntp clock-period 17180635
The router compensating for the clock slippage error.
The router
automatically updates this to compensate for the difference between the time on
the NTP server and the router clock. The number 17180635
was generated by the router and should not be manually modified.
http://www.cisco.com/univercd/cc/td/doc/product/atm/ls1010s/11_1/cr/lscrn.htm#12035
Cisco Config Maker
Cisco Ip Subnet
Calculator
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