BGP: community

[kozorezdi]

Hello All,

I am using the same community-list name for a few diffrent statements.

It's let me use the config shorter and more readable, but I can't modify/remove it.

Router(config)#do sh run | in transit

ip community-list standard transit-routes permit 900:4101

ip community-list standard transit-routes permit 900:4102

ip community-list standard transit-routes permit 900:4103

ip community-list standard transit-routes permit 900:4104

! I need to remove only one statement --> transit-routes permit 900:4104

Router(config)#no ip community-list standard transit-routes permit 900:4104

! as result I have removed all strings... (4101 - 4104)

Router(config)#do sh run | in transit

Router(config)#

Probably I missed something.  Please tell me, is it possible to modify such community-list in a different way?

Thank you in advance.

--

Have a nice day,

Dmitry

[Giuseppe Larosa]

Hello Dmitry,

write a new community-list with a different name with the statements that you like to keep

apply the new communiy-list in place of the old one

I tried to do what you did on a C7600 with same results

so it is like it happens for IP  ACLS if you delete one statement you delete all the ACL

so a possible approach is that above that avoids the transition from a not existing ACL to an ACL with only one line and so on

Hope to help

Giuseppe

[kozorezdi]

Giuseppe,

thank you for reply.  in this case i can use the action like this:

Router(config)#do sh run | in transit

ip community-list standard transit-routes permit 900:4101

ip community-list standard transit-routes permit 900:4102

ip community-list standard transit-routes permit 900:4103

ip community-list standard transit-routes permit 900:4104

Router(config)#no ip community-list standard transit-routes permit 900:4104

Router(config)# ip community-list standard transit-routes permit 900:4101

Router(config)# ip community-list standard transit-routes permit 900:4102

Router(config)# ip community-list standard transit-routes permit 900:4103

but I was thinking it should be simular to Named ACL than to standard ACL...

Thank you.

--

Have a nice day,

Dmitry

[Giuseppe Larosa · Accepted solution]

Hello Dmitry,

be aware that if you can change on the fly an ACL when it is applied in a route-map or in other way can have effects:

the first no command deletes the whole ACL so if applied meaning becomes "permit any"

as soon as you write the first line the ACL becomes an ACL with a single statement and so on.

The safer approach is to use a different name or to remove the line where you use it (for example in a route-map or in a neighbor statement) before making changes

Have a nice day you too

Hope to help

Giuseppe