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North American Network Operators Group Date Prev | Date Next | Date Index | Thread Index | Author Index | Historical Re: Regular Expressions ......
Hi, Sorry for pick up the historic thread. But why not a more simple and clear one? ip as-path access-list 1 permit ^[0-9]+$ ip as-path access-list 2 permit ^([0-9]+) ([0-9]+)$ ip as-path access-list 3 permit ^([0-9]+) ([0-9]+)([0-9]+)$ ip as-path access-list 4 permit .* It's quite clear, and you can expand it to whichever level you want. Correct me if i were wrong. regards, Yu Ning ------------------------------------------- (Mr.) Yu(2) Ning(2) ChinaNet Backbone Operation Networking Dep.,Datacom Bureau China Telecom.,Beijing(100088),P.R.C +86-10-66418105/66418121/66418123(fax) ------------------------------------------- ----- Original Message ----- From: "Peter T. Whiting" <[email protected]> To: "Ally Gudgeon" <[email protected]> Cc: <[email protected]> Sent: Friday, May 26, 2000 7:40 PM Subject: Re: Regular Expressions ...... > > > I see two problems. > > 1. _ matches the beginning of the string, the end of the string, > space, braces, comma, underscore or parentheses. What you probably > wanted in your regexp is a normal space. > > 2. * matches zero or more of the previous pattern, what you probably > wanted was a + (you want to force it to have at least one > digit.) > > Fixing either one of these will produce the results you are > looking for. I recommend fixing both. Also, note that you > can stack "beginning of string" or "end of string". The > following produce the same result. > > sho ip bgp reg ^_^^[0-9]*^^_^^_^[0-9]*$_$$ > sho ip bgp reg ^_^^[0-9]*$___$__[0-9]*$$_$ > sho ip bgp reg ^[0-9]*$ > > the point? Be careful with * and _. > > pete > > > > On Fri, May 26, 2000 at 10:07:50AM +0100, Ally Gudgeon wrote: > > > > Hi All, > > > > I am having a few problems getting my BGP filtering to work - and am > > experiencing some strange results.. > > > > I have two routers connected to a peering point, we have decided that we > > want to set local preferences of > > > > 110 to 1-deep AS-paths (as-path ACL 1) > > 100 to 2-deep AS-paths (as-path ACL 2) > > and 90 to 3-deep AS-paths (as-path ACL 3) > > and to not accept 4-deep AS-paths (as-path ACL 4) > > > > I have the following as-path ACLs to try to set that and am using route > > maps. > > > > ip as-path access-list 1 permit ^[0-9]*$ > > ip as-path access-list 2 permit ^[0-9]*_[0-9]*$ > > ip as-path access-list 3 permit ^[0-9]*_[0-9]*_[0-9]*$ > > ip as-path access-list 4 permit .* > > > > This appears to have failed miserably....It is not setting local prefs > > correctly if they are 3-deep and have a repetition of an AS number it sees > > it as 4-deep > > If they are 4 AS's deep it doesn't apply a local preference but if it knows > > it from our other core router it sets a local pref of 100 but prefers the > > direct route? > > > > (ALSO: If I do a sh ip bgp reg ^[0-9]*_[0-9]*$ it lists both 1-deep and > > 2-deep AS's....surely it should just list 2-deep?) > > > > Any help would be greatly appreciated!...... > > > > Thanks in advance.. > > > > > > Ally > > > > > > email - [email protected] > > ++++++++++++++++++++++++++++++++++++++++++++++++++++++++ > > This email and any files transmitted with it are confidential and intended > > solely for the use of the individual or entity to whom they are addressed. > > The views expressed in the email and files transmitted with it are those of > > the individual, not the company. If you have received this email in error > > please notify [email protected] > > +++++++++++++++++++++++++++++++++++++++++++++++++++++++++ > > > > > > > >
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