Thank you everyone for your response, The reason I am confused is not becasuse the NULL0 in routing table, that's the way eigrp does. The reason is when I set the "network 0.0.0.0" in eigrp, it distribute the 172.22.0.0 network to S0 side(I have another router running eigrp at S0 side, its routing table shows up 172.22.0.0 or 172.22.2.0/24 when I enable no summary).
Chuck, does network 0.0.0.0 mean to enable all interface to participate into route distribution? My idea is to put S0 in eigrp and S1 in BGP, while only set "network 192.168.1.0" won't put S1 into eigrp, thus won't distribute the 172.22.0.0 network info into S0 side. I am using IOS12.1.5(10T). Regards Wei ----- Original Message ----- From: "The Long and Winding Road" To: Sent: Thursday, January 16, 2003 2:37 AM Subject: Re: EIGRP network 0.0.0.0 to redistribute static route [7:61186] > ""The Long and Winding Road"" wrote in > message [EMAIL PROTECTED]">news:[EMAIL PROTECTED]... > > well, now that I've set it up, looked at it, and given it some thought, > the > > answer is really quite simple. > > being a simple person myself, I like it when answers are simple. think > > "classful nature of eigrp" > > > > see below > > > > > > ""Wei Zhu"" wrote in message > > [EMAIL PROTECTED]">news:[EMAIL PROTECTED]... > > > ---EIGRP 100--(S0)---R1---(S1)--BGP AS 200--- > > > > > > R1 > > > S0 192.168.1.1 255.255.255.240 > > > S1 172.22.2.1 255.255.255.0 > > > S0 side run EIGRP, S1 side run BGP > > > > > > (1) > > > router eigrp 200 > > > network 192.168.1.0 > > > > > > router bgp > > > nei XXXX remote-as XXX > > > > > > R1 will send 192.168.1.0 route info through S0, but won't send the > > > 172.22.2.0 network info. > > > > > > (2) > > > ip route 0.0.0.0 0.0.0.0 S1 > > > > > > router eigrp 200 > > > network 192.168.1.0 > > > redistrib static > > > > > > Everything works fine > > > > > > (3) > > > If using network 0.0.0.0 to redistribute static info as: > > > ip route 0.0.0.0 0.0.0.0 S1 > > > > > > router eigrp 200 > > > network 192.168.1.0 > > > network 0.0.0.0 > > > > > > In addition of distribute the 0.0.0.0, R1 will also distribute > 172.22.0.0 > > > (summury) network info through S0 > > > > first of all, you are not seeing the whole picture because of the limited > > numbers of interfaces you have in your basic setup. > > > > second of all, let me ask you a question. what exactly is 0.0.0.0? > > > > thirdly, having answered and understood what exactly 0.0.0.0 really > > represents, let me ask you another question. what happens when you put the > > entry "network 0.0.0.0" into the eigrp process? will eigrp still work if > you > > were to now remove the "network 192.168.1.0" statement? why not? > > > > this is starting to feel like another homily. > > > > > > > It will also put 172.22.0.0/16 null0 route entry into its routing table. > > > > nature of the beast. I don't believe it is true of all protocols, but some > > of them will automatically place a summary to null 0 when a summary is > > advertised out. This is done as proof against black holes and helps > prevent > > routing loops > > > > BTW, I enjoy your posts. Keep up the good work. > > > > > > > > Can anyone explain why this happens? > > > oh, you know what, while composing a reply to cebuano, I realized - you > probably have automaticic summarization enabled under eigrp > > enter the command "no auto-summary" and watch the staic to null 0 disappear. > > > > > > > > > > > > > > > > > > > > > > Thanks > > > Wei Message Posted at: http://www.groupstudy.com/form/read.php?f=7&i=61236&t=61236 -------------------------------------------------- FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
