RE: IP unnumbered [7:18250]
The Loopback Interface is useful in OSPF, BGP, for network management. If a loopback will have 2-3 uses anyway, why not throw in ip unnumbered. If someone is dead set against loopback, you could use interface serial 0/0 ip unnumbered interface ethernet 0/0 ip address 10.1.1.1 255.255.255.0 no keepalive The Ethernet interface would always be up!! ^-^-^-^-^-^-^-^-^-^-^ Bill Carter CCIE 5022 ^-^-^-^-^-^-^-^-^-^-^ -Original Message- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]]On Behalf Of Michael L. Williams Sent: Tuesday, September 04, 2001 5:49 PM To: [EMAIL PROTECTED] Subject: Re: IP unnumbered [7:18250] Dave, I agree totally with your statement, however, I don't understand why you say that if you use ip unnumbered pointing to a LoopBack interface that nullifies the point of using unnumbered (to save IPs). You can still use a single IP address on a LoopBack not waste more by putting separate IPs on each p-t-p link.. Mike W. MADMAN wrote in message [EMAIL PROTECTED]">news:[EMAIL PROTECTED]... Brett gives a good example that will work just fine but I would not recommend using IP unnumbered. With RFC 1918 you have more IP addesses than your going to need so no problems with using registered addresses on p-to-p links. troubleshooting also becomes trickier but if you insist on using them then use a loopback interface, but then a primary argument is shot, burning IP addreses. Dave Brett Hairbottle wrote: Hi Instead of using a numbered link you can use ip unnumbered to connect sites. Example: Router A: interface fastethernet 0 ip address 10.100.2.1 255.255.255.0 interface serial 0 ip unnumbered fasthethernet 0 Router B: interface fastethernet 0 ip address 10.100.31 255.255.255.0 interface serial 0 ip unnumbered fasthethernet 0 now instead of assigning a ip address to each serial port you can use the ip unnumbered command Brett Hairbottle Network Administrator CCNA - Original Message - From: sami natour To: Sent: Sunday, September 02, 2001 10:33 PM Subject: IP unnumbered [7:18250] Hello everybody, I know how to cinfigure IP unumbered but I do not know any practical scenario that I make use of this feature.Any body has specific scanrios where I can use ip unnumbered . Regards , sami __ Do You Yahoo!? Get email alerts NEW webcam video instant messaging with Yahoo! Messenger http://im.yahoo.com -- David Madland Sr. Network Engineer CCIE# 2016 Qwest Communications Int. Inc. [EMAIL PROTECTED] 612-664-3367 Emotion should reflect reason not guide it Message Posted at: http://www.groupstudy.com/form/read.php?f=7i=18604t=18250 -- FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
RE: IP unnumbered [7:18250]
In previous network monitoring experience, I have had it happen to me where a customer unplugs the lan to do some work, but leaves the serial in, thinking theyre doing us a favor. Brian Sonic Whalen Success = Preparation + Opportunity On Wed, 5 Sep 2001, Bill Carter wrote: The Loopback Interface is useful in OSPF, BGP, for network management. If a loopback will have 2-3 uses anyway, why not throw in ip unnumbered. If someone is dead set against loopback, you could use interface serial 0/0 ip unnumbered interface ethernet 0/0 ip address 10.1.1.1 255.255.255.0 no keepalive The Ethernet interface would always be up!! ^-^-^-^-^-^-^-^-^-^-^ Bill Carter CCIE 5022 ^-^-^-^-^-^-^-^-^-^-^ -Original Message- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]]On Behalf Of Michael L. Williams Sent: Tuesday, September 04, 2001 5:49 PM To: [EMAIL PROTECTED] Subject: Re: IP unnumbered [7:18250] Dave, I agree totally with your statement, however, I don't understand why you say that if you use ip unnumbered pointing to a LoopBack interface that nullifies the point of using unnumbered (to save IPs). You can still use a single IP address on a LoopBack not waste more by putting separate IPs on each p-t-p link.. Mike W. MADMAN wrote in message [EMAIL PROTECTED]">news:[EMAIL PROTECTED]... Brett gives a good example that will work just fine but I would not recommend using IP unnumbered. With RFC 1918 you have more IP addesses than your going to need so no problems with using registered addresses on p-to-p links. troubleshooting also becomes trickier but if you insist on using them then use a loopback interface, but then a primary argument is shot, burning IP addreses. Dave Brett Hairbottle wrote: Hi Instead of using a numbered link you can use ip unnumbered to connect sites. Example: Router A: interface fastethernet 0 ip address 10.100.2.1 255.255.255.0 interface serial 0 ip unnumbered fasthethernet 0 Router B: interface fastethernet 0 ip address 10.100.31 255.255.255.0 interface serial 0 ip unnumbered fasthethernet 0 now instead of assigning a ip address to each serial port you can use the ip unnumbered command Brett Hairbottle Network Administrator CCNA - Original Message - From: sami natour To: Sent: Sunday, September 02, 2001 10:33 PM Subject: IP unnumbered [7:18250] Hello everybody, I know how to cinfigure IP unumbered but I do not know any practical scenario that I make use of this feature.Any body has specific scanrios where I can use ip unnumbered . Regards , sami __ Do You Yahoo!? Get email alerts NEW webcam video instant messaging with Yahoo! Messenger http://im.yahoo.com -- David Madland Sr. Network Engineer CCIE# 2016 Qwest Communications Int. Inc. [EMAIL PROTECTED] 612-664-3367 Emotion should reflect reason not guide it Message Posted at: http://www.groupstudy.com/form/read.php?f=7i=18658t=18250 -- FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
Re: IP unnumbered [7:18250]
Hi Instead of using a numbered link you can use ip unnumbered to connect sites. Example: Router A: interface fastethernet 0 ip address 10.100.2.1 255.255.255.0 interface serial 0 ip unnumbered fasthethernet 0 Router B: interface fastethernet 0 ip address 10.100.31 255.255.255.0 interface serial 0 ip unnumbered fasthethernet 0 now instead of assigning a ip address to each serial port you can use the ip unnumbered command Brett Hairbottle Network Administrator CCNA - Original Message - From: sami natour To: Sent: Sunday, September 02, 2001 10:33 PM Subject: IP unnumbered [7:18250] Hello everybody, I know how to cinfigure IP unumbered but I do not know any practical scenario that I make use of this feature.Any body has specific scanrios where I can use ip unnumbered . Regards , sami __ Do You Yahoo!? Get email alerts NEW webcam video instant messaging with Yahoo! Messenger http://im.yahoo.com Message Posted at: http://www.groupstudy.com/form/read.php?f=7i=18465t=18250 -- FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
Re: IP unnumbered [7:18250]
Brett gives a good example that will work just fine but I would not recommend using IP unnumbered. With RFC 1918 you have more IP addesses than your going to need so no problems with using registered addresses on p-to-p links. troubleshooting also becomes trickier but if you insist on using them then use a loopback interface, but then a primary argument is shot, burning IP addreses. Dave Brett Hairbottle wrote: Hi Instead of using a numbered link you can use ip unnumbered to connect sites. Example: Router A: interface fastethernet 0 ip address 10.100.2.1 255.255.255.0 interface serial 0 ip unnumbered fasthethernet 0 Router B: interface fastethernet 0 ip address 10.100.31 255.255.255.0 interface serial 0 ip unnumbered fasthethernet 0 now instead of assigning a ip address to each serial port you can use the ip unnumbered command Brett Hairbottle Network Administrator CCNA - Original Message - From: sami natour To: Sent: Sunday, September 02, 2001 10:33 PM Subject: IP unnumbered [7:18250] Hello everybody, I know how to cinfigure IP unumbered but I do not know any practical scenario that I make use of this feature.Any body has specific scanrios where I can use ip unnumbered . Regards , sami __ Do You Yahoo!? Get email alerts NEW webcam video instant messaging with Yahoo! Messenger http://im.yahoo.com -- David Madland Sr. Network Engineer CCIE# 2016 Qwest Communications Int. Inc. [EMAIL PROTECTED] 612-664-3367 Emotion should reflect reason not guide it Message Posted at: http://www.groupstudy.com/form/read.php?f=7i=18475t=18250 -- FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
Re: IP unnumbered [7:18250]
Dave, I agree totally with your statement, however, I don't understand why you say that if you use ip unnumbered pointing to a LoopBack interface that nullifies the point of using unnumbered (to save IPs). You can still use a single IP address on a LoopBack not waste more by putting separate IPs on each p-t-p link.. Mike W. MADMAN wrote in message [EMAIL PROTECTED]">news:[EMAIL PROTECTED]... Brett gives a good example that will work just fine but I would not recommend using IP unnumbered. With RFC 1918 you have more IP addesses than your going to need so no problems with using registered addresses on p-to-p links. troubleshooting also becomes trickier but if you insist on using them then use a loopback interface, but then a primary argument is shot, burning IP addreses. Dave Brett Hairbottle wrote: Hi Instead of using a numbered link you can use ip unnumbered to connect sites. Example: Router A: interface fastethernet 0 ip address 10.100.2.1 255.255.255.0 interface serial 0 ip unnumbered fasthethernet 0 Router B: interface fastethernet 0 ip address 10.100.31 255.255.255.0 interface serial 0 ip unnumbered fasthethernet 0 now instead of assigning a ip address to each serial port you can use the ip unnumbered command Brett Hairbottle Network Administrator CCNA - Original Message - From: sami natour To: Sent: Sunday, September 02, 2001 10:33 PM Subject: IP unnumbered [7:18250] Hello everybody, I know how to cinfigure IP unumbered but I do not know any practical scenario that I make use of this feature.Any body has specific scanrios where I can use ip unnumbered . Regards , sami __ Do You Yahoo!? Get email alerts NEW webcam video instant messaging with Yahoo! Messenger http://im.yahoo.com -- David Madland Sr. Network Engineer CCIE# 2016 Qwest Communications Int. Inc. [EMAIL PROTECTED] 612-664-3367 Emotion should reflect reason not guide it Message Posted at: http://www.groupstudy.com/form/read.php?f=7i=18510t=18250 -- FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
Re: IP unnumbered [7:18250]
At this point, it think it would be good to mention that (IMHO) it's best to use the LoopBack interface for ip unnumbered because it can never go down.. In the config snipet you gave, your Serial0 couldn't communicate if FastEthernet0 went down. I do believe that with some version of 12.x, however, Cisco has made it so that even if the interface goes down, the unnumbered interface can still use it's IP, so be sure to check your IOS version, and see if that's the case.. But, that's just another good reason to use LoopBack because then you don't have to worry about that.. =) Mike W. Brett Hairbottle wrote in message [EMAIL PROTECTED]">news:[EMAIL PROTECTED]... Hi Instead of using a numbered link you can use ip unnumbered to connect sites. Example: Router A: interface fastethernet 0 ip address 10.100.2.1 255.255.255.0 interface serial 0 ip unnumbered fasthethernet 0 Router B: interface fastethernet 0 ip address 10.100.31 255.255.255.0 interface serial 0 ip unnumbered fasthethernet 0 now instead of assigning a ip address to each serial port you can use the ip unnumbered command Brett Hairbottle Network Administrator CCNA - Original Message - From: sami natour To: Sent: Sunday, September 02, 2001 10:33 PM Subject: IP unnumbered [7:18250] Hello everybody, I know how to cinfigure IP unumbered but I do not know any practical scenario that I make use of this feature.Any body has specific scanrios where I can use ip unnumbered . Regards , sami __ Do You Yahoo!? Get email alerts NEW webcam video instant messaging with Yahoo! Messenger http://im.yahoo.com Message Posted at: http://www.groupstudy.com/form/read.php?f=7i=18509t=18250 -- FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
Re: IP unnumbered [7:18250]
Agree, you don't use as many address with LB's as p-to-p networks but the primary point I was trying to make before I rambled is that there is really no good reason IMHO to ip unnumbered. Dave Michael L. Williams wrote: Dave, I agree totally with your statement, however, I don't understand why you say that if you use ip unnumbered pointing to a LoopBack interface that nullifies the point of using unnumbered (to save IPs). You can still use a single IP address on a LoopBack not waste more by putting separate IPs on each p-t-p link.. Mike W. MADMAN wrote in message [EMAIL PROTECTED]">news:[EMAIL PROTECTED]... Brett gives a good example that will work just fine but I would not recommend using IP unnumbered. With RFC 1918 you have more IP addesses than your going to need so no problems with using registered addresses on p-to-p links. troubleshooting also becomes trickier but if you insist on using them then use a loopback interface, but then a primary argument is shot, burning IP addreses. Dave Brett Hairbottle wrote: Hi Instead of using a numbered link you can use ip unnumbered to connect sites. Example: Router A: interface fastethernet 0 ip address 10.100.2.1 255.255.255.0 interface serial 0 ip unnumbered fasthethernet 0 Router B: interface fastethernet 0 ip address 10.100.31 255.255.255.0 interface serial 0 ip unnumbered fasthethernet 0 now instead of assigning a ip address to each serial port you can use the ip unnumbered command Brett Hairbottle Network Administrator CCNA - Original Message - From: sami natour To: Sent: Sunday, September 02, 2001 10:33 PM Subject: IP unnumbered [7:18250] Hello everybody, I know how to cinfigure IP unumbered but I do not know any practical scenario that I make use of this feature.Any body has specific scanrios where I can use ip unnumbered . Regards , sami __ Do You Yahoo!? Get email alerts NEW webcam video instant messaging with Yahoo! Messenger http://im.yahoo.com -- David Madland Sr. Network Engineer CCIE# 2016 Qwest Communications Int. Inc. [EMAIL PROTECTED] 612-664-3367 Emotion should reflect reason not guide it -- David Madland Sr. Network Engineer CCIE# 2016 Qwest Communications Int. Inc. [EMAIL PROTECTED] 612-664-3367 Emotion should reflect reason not guide it Message Posted at: http://www.groupstudy.com/form/read.php?f=7i=18514t=18250 -- FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
RE: IP unnumbered [7:18250]
Sure, IP unnumbered is frequently used by ISP's to save address space and for ease of configuration. Lets say you have a 7513 with 280 T1 customers on it, that would mean wasting 280 /30 IP blocks just on interface transit, so why use those IP's if you don't have a specific reason to? That is one of the bigger applications. You can also use it if you have only one IP address routed to you and you want to use it for NAT. You can use IP unnumbered on the serial, assign the ethernet a private IP, use the public for the NAT pool and map port 23 on the public IP address to port 23 on the private ethernet IP for telnet access. Hope this is what you were looking for. Guy -Original Message- From: sami natour To: [EMAIL PROTECTED] Sent: 9/2/01 4:33 PM Subject: IP unnumbered [7:18250] Hello everybody, I know how to cinfigure IP unumbered but I do not know any practical scenario that I make use of this feature.Any body has specific scanrios where I can use ip unnumbered . Regards , sami __ Do You Yahoo!? Get email alerts NEW webcam video instant messaging with Yahoo! Messenger http://im.yahoo.com Message Posted at: http://www.groupstudy.com/form/read.php?f=7i=18255t=18250 -- FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
Re: IP unnumbered [7:18250]
When IP addresses are hard to come by (remember: a /30 subnet takes 4 addresses). When you don't want to deal with administering tons of /30 subnets that would comprise the WAN links. There are probably other reasons. These were the first to come to mind. Ken Diliberto CCNA, CCNP, Ericsson E1 E2, CCIE Pre-written NRA Life Member, American Airlines Advantage Gold Co-Author Investigating Computer Crime ;-) I'd say I'm sorry, but I couldn't resist getting in on the fun. :-) sami natour 09/02/01 03:33PM Hello everybody, I know how to cinfigure IP unumbered but I do not know any practical scenario that I make use of this feature.Any body has specific scanrios where I can use ip unnumbered . Regards , sami [snip] Message Posted at: http://www.groupstudy.com/form/read.php?f=7i=18257t=18250 -- FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
Re: IP unnumbered [7:18250]
you might use it if you had say an access-server e.g you got group-async 1 and group-async the router wont let you do 'ip address 10.0.0.1 255.0.0.0 on both interfaces so instead you would assign 10.0.0.1 to loopback 0 and then in group-async 1 2 ip unnumbered loopback 0 thus giving them both the same ip :) Justin At 04:33 PM 2/09/01 -0400, you wrote: Hello everybody, I know how to cinfigure IP unumbered but I do not know any practical scenario that I make use of this feature.Any body has specific scanrios where I can use ip unnumbered . Regards , sami __ Do You Yahoo!? Get email alerts NEW webcam video instant messaging with Yahoo! Messenger http://im.yahoo.com Message Posted at: http://www.groupstudy.com/form/read.php?f=7i=18260t=18250 -- FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
RE: IP unnumbered [7:18250]
Another advantage of IP unumbered, is if you have say 250 T1 customers hanging off a router, and you default router them out there serial interface: ip route 0.0.0.0 0.0.0.0 s0 then, if you ever want to move customers to another router, you don't have to have access to there router to do anything, nd don't have to go renumbering any interfaces either. Brian On Sun, 2 Sep 2001, Lupi, Guy wrote: Sure, IP unnumbered is frequently used by ISP's to save address space and for ease of configuration. Lets say you have a 7513 with 280 T1 customers on it, that would mean wasting 280 /30 IP blocks just on interface transit, so why use those IP's if you don't have a specific reason to? That is one of the bigger applications. You can also use it if you have only one IP address routed to you and you want to use it for NAT. You can use IP unnumbered on the serial, assign the ethernet a private IP, use the public for the NAT pool and map port 23 on the public IP address to port 23 on the private ethernet IP for telnet access. Hope this is what you were looking for. Guy -Original Message- From: sami natour To: [EMAIL PROTECTED] Sent: 9/2/01 4:33 PM Subject: IP unnumbered [7:18250] Hello everybody, I know how to cinfigure IP unumbered but I do not know any practical scenario that I make use of this feature.Any body has specific scanrios where I can use ip unnumbered . Regards , sami __ Do You Yahoo!? Get email alerts NEW webcam video instant messaging with Yahoo! Messenger http://im.yahoo.com I'm buying / selling used CISCO gear!! email me for a quote Brian Feeny, CCIE #8036 Netjam, LLC [EMAIL PROTECTED] http://www.netjam.net VISA/MC/AMEX/COD phone: 318-212-0245 30 day warranty fax: 318-212-0246 Message Posted at: http://www.groupstudy.com/form/read.php?f=7i=18261t=18250 -- FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
