Need more documents for regexp at /routing/filter/community-list

[ferrets]

I’m trying to use community-list to filter routes or modify certain communities, but it’s really hard to achieve using regexp.

The help page didn’t include any examples for this, so I had to test it on my own, encountering numerous failures along the way. For example:

1. Adding regexp items in Winbox fails:

• I can’t add new items via Winbox with type=regexp.
• No matter what I enter in the “Regexp” box, from regex patterns tested successfully on regex101.com to empty string, RouterOS always returns “invalid regexp”.

2. Adding regexp items behaves strangely:

• I can add new items via the console with type=regexp, but the content of “regexp” displays differently in Winbox versus the console (what the heck?).
• After adding a regexp item via the console, I can modify the “regexp” content in Winbox without triggering the “invalid regexp” error.

3. Inconsistent behavior when applying the list in filtering rules:

• The list works for matching routes but fails to delete communities.
• Here are the two community lists I configured:

`/routing filter community-list

add list=dn42_connection_info_regex regexp=“64511\:\d”

add list=dn42_connection_info communities=“64511:1,64511:2,64511:3,64511:4,64511:5,64511:6,64511:7,64511:8,64511:9,64511:10,64511:11,64511:12,64511:13,64511:14,64511:15,64511:16,64511:17,64511:18,64511:19,64511:20,64511:21,64511:22,64511:23,64511:24,64511:25,64511:26,64511:27,64511:28,64511:29,64511:30,64511:31,64511:32,64511:33,64511:34,64511:35”`

4. Testing filtering rules:
   (Note: In Winbox, the regexp is set to "64511\:[\d|[1-3][0-9]]".)

• if (bgp-communities any-list dn42_connection_info_regex) { delete bgp-communities dn42_connection_info_regex; accept; }
  → Matches correctly, but deletion fails.

• if (bgp-communities any-list dn42_connection_info) { delete bgp-communities dn42_connection_info_regex; accept; }
  → Matches correctly, but deletion fails.

• if (bgp-communities any-list dn42_connection_info_regex) { delete bgp-communities dn42_connection_info; accept; }
  → Matches correctly, deletion succeeds.

• if (bgp-communities any-list dn42_connection_info) { delete bgp-communities dn42_connection_info; accept; }
  → Matches correctly, deletion succeeds.

Regexp is incredibly useful for configuration and offers great flexibility. I hope there will be more documentation and examples on how to properly configure it for route filtering.

[mrz]

1. Winbox problem confirmed.

2. For CLI strings special characters need to be escaped:
   Scripting - RouterOS - MikroTik Documentation

3. As stated in the documentation. community list entry with just a regexp parameter is used only for matching.

[ferrets]

2. Typing in CLI should be add list=dn42_connection_info_regex regexp=“64511\\:\\d”, the codes I’ve pasted are copied from export. But the real problem is that content in CLI/export is different from content shown in winbox.

3. I’ve also tried using regex directly in filter rule like delete bgp-communities regexp "64511\:[\d|[1-3][0-9]]"; , but still not working.
   

   
   
   
   

I’ve read the document, but it just noticed that regex can not using to append. So I think it means that deletion or filtering should works. If only matching is supported, how about changing the description?