Kvm.la - 路由
type: channel
link: https://kvm.la/tag/%E8%B7%AF%E7%94%B1/
items: 思科配置回顾备忘录
items: 思科路由不收IX路由表问题

思科配置回顾备忘录
type: item
date: 2025-09-14T06:16:00+00:00
description: #查看邻居 show ip bgp neighbors <peer-ip> #拒收默认路由规则 ip prefix-list DEFAULT-ROUTE-v4 seq 5 deny 0.0.0.0/0 ipv6 prefix-list DEFAULT-ROUTE-v6 seq 5 deny ::/0 #刷新收取路由 clear ip bgp <peer-ip> soft in #查看BGP连接状态 show ip bgp summary show bgp ipv6 unicast summary #筛选配置内容 show running-config | section router bgp #查看bgp邻居 show bgp ipv6 unicast neighbors <peer-ipv6> show bgp ipv4 unicast neighbors <peer-ipv4> #查看网卡状态信息 show ip interface brief #查看宣告路由表 show bgp ipv6 unicast neighbors <peer-ipv6> advertised-routes show bgp ipv4 unicast neighbors <peer-ipv4> advertised-routes router bgp 65000 no bgp enforce-first-as #关闭拒收一个as非peer as的路由 neighbor <peer-ipv4> default-originate #BGP发送默认路由

思科路由不收IX路由表问题
type: item
date: 2025-09-13T15:35:00+00:00
description: 帮人配置个思科路踩到个坑：翻了半天文档才发现ASR默认开启了 bgp enforce-first-as，导致路由表里首个 AS 不是peer AS 的前缀都在Local Policy Denied Prefixes里面。 router bgp 65536 no bgp enforce-first-as IX在发送交换路由的时候把自身AS过滤掉了，导致无法收表。 之前也用了chatgpt寻找答案，关键点也提到了IX在as-path过滤掉了自生AS，但是仍然没有正确解决思路都没提到，反而一直让route-map的规则里面找配置问题和重新配置BGP Session。