Re: Loopback interface IP address
Though I do not have an in-depth knowledge in loopback interface. I would like to add on a bit of my experience working on it. I have tried to configure a loopback interface for NAT kind of config (For Internet access ) with the interface as ip nat outside. It did not work. Eventually, I have to remove it and put the nat outside statement into my E0.(E1 is my ip nat inside)Surprising that works!! I was told that loopback interface is only for intranet configuration. Is this really true, I am not so sure?? :)Well that's was my experience regards "Alex Lee" [EMAIL PROTECTED] wrote in message 9ai0a7$7fb$[EMAIL PROTECTED]">news:9ai0a7$7fb$[EMAIL PROTECTED]... Group, I was looking at some documents at CCO, and noticed that sometimes their examples use /32 IP address like : interface loopback 0 ip address 172.16.254.3 255.255.255.255 Can someone help me to understand reason behind in using this type of address in the configuration ? _ FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
Re: Loopback interface IP address
Group, I was looking at some documents at CCO, and noticed that sometimes their examples use /32 IP address like : interface loopback 0 ip address 172.16.254.3 255.255.255.255 Can someone help me to understand reason behind in using this type of address in the configuration ? _ FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
Re: Loopback interface IP address
Reasons. Plural. 1. This is a loopback interface. It is always up. Which means, if you statically or dynamically make this /32 host route accessible via anywhere in the network, you can connect via IP to this address instead of each regular interface (serial and ethernet interfaces go down). So as long as one of your regular interfaces are up, you can reach the router via this loopback address. This could be especially useful for telnet/ssh remote access, snmp, and icmp testing/troubleshooting/managing of a router. 2. Router-id in routing protocols is determined by the highest loopback address (assuming that one is configured). 3. You can use `ip unnumbered' to a loopback address. I'm sure there are other reasons, but those three are good enough for me. -dre ""Alex Lee"" [EMAIL PROTECTED] wrote in message 9ai0a7$7fb$[EMAIL PROTECTED]">news:9ai0a7$7fb$[EMAIL PROTECTED]... Group, I was looking at some documents at CCO, and noticed that sometimes their examples use /32 IP address like : interface loopback 0 ip address 172.16.254.3 255.255.255.255 Can someone help me to understand reason behind in using this type of address in the configuration ? _ FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
RE: Loopback interface IP address
A loopback interface is basically ina network of it's own. it is not connected to another Interface nor does it particcipate in the transport of data (in it's normal form atleast.) However it is used (specially in a dynamic routing enviro) as a "reliable Interface" since it would be available as long as at least one interface on the unit is up. Now for the /32 mask. Well why waste more IPs than needed. All you need is 1 is this "broadcast domain" there is nothing else connected to this interface physically. -Original Message- From: perryb To: [EMAIL PROTECTED] Sent: 4/5/2001 9:28 AM Subject: Fw: Loopback interface IP address - Original Message - From: "Alex Lee" [EMAIL PROTECTED] Newsgroups: groupstudy.cisco To: [EMAIL PROTECTED] Sent: Thursday, April 05, 2001 6:34 AM Subject: Re: Loopback interface IP address Group, I was looking at some documents at CCO, and noticed that sometimes their examples use /32 IP address like : interface loopback 0 ip address 172.16.254.3 255.255.255.255 Can someone help me to understand reason behind in using this type of address in the configuration ? _ FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
RE: Loopback interface IP address
A loopback interface is basically ina network of it's own. it is not connected to another Interface nor does it particcipate in the transport of data (in it's normal form atleast.) However it is used (specially in a dynamic routing enviro) as a "reliable Interface" since it would be available as long as at least one interface on the unit is up. Now for the /32 mask. Well why waste more IPs than needed. All you need is 1 is this "broadcast domain" there is nothing else connected to this interface physically. OSPF has special treatment for /32 host routes, so I tend not to use them for loopbacks -- the entries in the link state database can look weird otherwise. I've also seen some weirdnesses with /30, so I'm apt to use a /29 subnet. I wouldn't want my loopback addresses accessible from the public internet, so I will use private space -- and am not very worried about conserving it. _ FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
