Hi guys, I'm doing a "split routing table" on my router, and I'm importing routes into specific kernel routing tables via bird. So I'm doing some strange routing by using ip rule.
[root@archlinux ~]# ip -4 rule 0: from all lookup local 32751: from 134.195.121.118 lookup 101 32752: from all iif Tanuki_IX lookup 147 32753: from all iif ens19 lookup 147 32754: from all iif cu_gre6 lookup 247 32755: from all iif cu lookup 147 32756: from all iif openvpn_stuix.5 lookup 247 32757: from all iif openvpn_stuix lookup 147 32758: from all iif openvpn_c1v lookup 147 32759: from all iif openvpn_c1v.5 lookup 247 32760: from all iif openvpn_Eric.5 lookup 247 32761: from all iif openvpn_Eric lookup 147 32762: from all iif ll-ix lookup 147 32763: from all iif ll-ix_gre6 lookup 247 32764: from all iif KSKB lookup 147 32765: from all iif KSKB_gre6 lookup 247 32766: from all lookup main 32767: from all lookup default As you could see, IPv4 from 134.195.121.118/32 will using table 101 which only contain [root@archlinux ~]# ip -4 route show table 101 default via 33.0.0.6 dev openvpn_Eric [root@archlinux ~]# When I am mtr to 8.8.8.8, it still uses the main route table NOT table 101 which does not follow the ip rule. [root@archlinux ~]# mtr -a 134.195.121.118 8.8.8.8 [root@archlinux ~]# tcpdump -i any host 134.195.121.118 tcpdump: data link type LINUX_SLL2 tcpdump: verbose output suppressed, use -v[v]... for full protocol decode listening on any, link-type LINUX_SLL2 (Linux cooked v2), snapshot length 262144 bytes 13:30:11.991460 ens18 Out IP archlinux > dns.google: ICMP echo request, id 65299, seq 33008, length 44 13:30:11.998947 openvpn_Eric Out IP archlinux.palace-2 > 172.17.0.1.palace-2: UDP, length 28 13:30:11.999059 openvpn_Eric Out IP archlinux.33915 > 172.17.0.1.palace-2: UDP, length 28 13:30:11.999384 openvpn_Eric Out IP archlinux.27004 > 172.17.0.1.palace-2: UDP, length 28 13:30:12.006020 openvpn_Eric Out IP archlinux.palace-2 > 59.200.0.1.palace-2: UDP, length 28 13:30:12.006096 openvpn_Eric Out IP archlinux.33915 > 59.200.0.1.palace-2: UDP, length 28 13:30:12.006136 openvpn_Eric Out IP archlinux.27004 > 59.200.0.1.palace-2: UDP, length 28 13:30:12.017489 openvpn_Eric Out IP archlinux.palace-2 > 208.99.49.1.palace-2: UDP, length 28 13:30:12.017628 openvpn_Eric Out IP archlinux.33915 > 208.99.49.1.palace-2: UDP, length 28 13:30:12.017650 openvpn_Eric Out IP archlinux.27004 > 208.99.49.1.palace-2: UDP, length 28 13:30:12.023034 openvpn_Eric Out IP archlinux.palace-2 > 172.23.89.1.palace-2: UDP, length 28 13:30:12.023147 openvpn_Eric Out IP archlinux.33915 > 172.23.89.1.palace-2: UDP, length 28 13:30:12.023202 openvpn_Eric Out IP archlinux.27004 > 172.23.89.1.palace-2: UDP, length 28 13:30:12.027182 openvpn_Eric Out IP archlinux.palace-2 > 172.17.0.1.24452: UDP, length 28 13:30:12.027203 openvpn_Eric Out IP archlinux.33915 > 172.17.0.1.24452: UDP, length 28 13:30:12.027212 openvpn_Eric Out IP archlinux.27004 > 172.17.0.1.24452: UDP, length 28 13:30:12.031218 openvpn_Eric Out IP archlinux.palace-2 > 59.200.0.1.24452: UDP, length 28 13:30:12.031235 openvpn_Eric Out IP archlinux.33915 > 59.200.0.1.24452: UDP, length 28 13:30:12.031243 openvpn_Eric Out IP archlinux.27004 > 59.200.0.1.24452: UDP, length 28 13:30:12.036170 openvpn_Eric Out IP archlinux.palace-2 > 208.99.49.1.24452: UDP, length 28 13:30:12.036192 openvpn_Eric Out IP archlinux.33915 > 208.99.49.1.24452: UDP, length 28 13:30:12.036200 openvpn_Eric Out IP archlinux.27004 > 208.99.49.1.24452: UDP, length 28 13:30:12.040852 openvpn_Eric Out IP archlinux.palace-2 > 172.23.89.1.24452: UDP, length 28 13:30:12.040873 openvpn_Eric Out IP archlinux.33915 > 172.23.89.1.24452: UDP, length 28 13:30:12.040881 openvpn_Eric Out IP archlinux.27004 > 172.23.89.1.24452: UDP, length 28 13:30:12.046089 openvpn_Eric Out IP archlinux.palace-2 > 172.17.0.1.24453: UDP, length 28 13:30:12.046119 openvpn_Eric Out IP archlinux.33915 > 172.17.0.1.24453: UDP, length 28 13:30:12.046138 openvpn_Eric Out IP archlinux.27004 > 172.17.0.1.24453: UDP, length 28 13:30:12.051427 openvpn_Eric Out IP archlinux.palace-2 > 59.200.0.1.24453: UDP, length 28 13:30:12.051453 openvpn_Eric Out IP archlinux.33915 > 59.200.0.1.24453: UDP, length 28 13:30:12.051467 openvpn_Eric Out IP archlinux.27004 > 59.200.0.1.24453: UDP, length 28 13:30:12.055046 openvpn_Eric Out IP archlinux.palace-2 > 208.99.49.1.24453: UDP, length 28 13:30:12.055075 openvpn_Eric Out IP archlinux.33915 > 208.99.49.1.24453: UDP, length 28 13:30:12.055085 openvpn_Eric Out IP archlinux.27004 > 208.99.49.1.24453: UDP, length 28 13:30:12.058847 openvpn_Eric Out IP archlinux.palace-2 > 172.23.89.1.24453: UDP, length 28 13:30:12.058874 openvpn_Eric Out IP archlinux.33915 > 172.23.89.1.24453: UDP, length 28 13:30:12.058886 openvpn_Eric Out IP archlinux.27004 > 172.23.89.1.24453: UDP, length 28 13:30:12.091913 ens18 Out IP archlinux > dns.google: ICMP echo request, id 65299, seq 33009, length 44 13:30:12.096047 openvpn_Eric Out IP archlinux.palace-2 > 7.254.0.1.palace-2: UDP, length 28 13:30:12.096081 openvpn_Eric Out IP archlinux.33915 > 7.254.0.1.palace-2: UDP, length 28 13:30:12.096092 openvpn_Eric Out IP archlinux.27004 > 7.254.0.1.palace-2: UDP, length 28 13:30:12.101389 openvpn_Eric Out IP archlinux.palace-2 > 7.254.0.1.24452: UDP, length 28 13:30:12.101409 openvpn_Eric Out IP archlinux.33915 > 7.254.0.1.24452: UDP, length 28 13:30:12.101422 openvpn_Eric Out IP archlinux.27004 > 7.254.0.1.24452: UDP, length 28 13:30:12.192666 ens18 Out IP archlinux > dns.google: ICMP echo request, id 65299, seq 33010, length 44 13:30:12.293006 ens18 Out IP archlinux > dns.google: ICMP echo request, id 65299, seq 33011, length 44 13:30:12.393416 ens18 Out IP archlinux > dns.google: ICMP echo request, id 65299, seq 33012, length 44 13:30:12.494029 ens18 Out IP archlinux > dns.google: ICMP echo request, id 65299, seq 33013, length 44 13:30:12.607660 ens18 Out IP archlinux > dns.google: ICMP echo request, id 65299, seq 33014, length 44 13:30:12.679414 ens18 Out IP archlinux > dns.google: ICMP echo request, id 65299, seq 33015, length 44 13:30:12.966665 ens18 Out IP archlinux > dns.google: ICMP echo request, id 65299, seq 33019, length 44 13:30:13.039053 ens18 Out IP archlinux > dns.google: ICMP echo request, id 65299, seq 33020, length 44 13:30:14.045371 ens18 Out IP archlinux > dns.google: ICMP echo request, id 65299, seq 33034, length 44 13:30:14.116878 ens18 Out IP archlinux > dns.google: ICMP echo request, id 65299, seq 33035, length 44 13:30:14.188702 ens18 Out IP archlinux > dns.google: ICMP echo request, id 65299, seq 33036, length 44 13:30:14.260455 ens18 Out IP archlinux > dns.google: ICMP echo request, id 65299, seq 33037, length 44 13:30:14.332277 ens18 Out IP archlinux > dns.google: ICMP echo request, id 65299, seq 33038, length 44 13:30:14.404019 ens18 Out IP archlinux > dns.google: ICMP echo request, id 65299, seq 33039, length 44 13:30:14.475861 ens18 Out IP archlinux > dns.google: ICMP echo request, id 65299, seq 33040, length 44 13:30:14.547705 ens18 Out IP archlinux > dns.google: ICMP echo request, id 65299, seq 33041, length 44 13:30:14.619529 ens18 Out IP archlinux > dns.google: ICMP echo request, id 65299, seq 33042, length 44 13:30:14.691361 ens18 Out IP archlinux > dns.google: ICMP echo request, id 65299, seq 33043, length 44 13:30:14.763157 ens18 Out IP archlinux > dns.google: ICMP echo request, id 65299, seq 33044, length 44 13:30:14.834959 ens18 Out IP archlinux > dns.google: ICMP echo request, id 65299, seq 33045, length 44 13:30:14.906978 ens18 Out IP archlinux > dns.google: ICMP echo request, id 65299, seq 33046, length 44 13:30:14.978577 ens18 Out IP archlinux > dns.google: ICMP echo request, id 65299, seq 33047, length 44 13:30:15.050371 ens18 Out IP archlinux > dns.google: ICMP echo request, id 65299, seq 33048, length 44 13:30:15.122227 ens18 Out IP archlinux > dns.google: ICMP echo request, id 65299, seq 33049, length 44 13:30:15.193915 ens18 Out IP archlinux > dns.google: ICMP echo request, id 65299, seq 33050, length 44 13:30:15.265629 ens18 Out IP archlinux > dns.google: ICMP echo request, id 65299, seq 33051, length 44 13:30:15.325557 openvpn_Eric Out IP archlinux.palace-2 > root-mia-01.zerotier.com.palace-2: UDP, length 137 13:30:15.325578 openvpn_Eric Out IP archlinux.33915 > root-mia-01.zerotier.com.palace-2: UDP, length 137 13:30:15.325586 openvpn_Eric Out IP archlinux.27004 > root-mia-01.zerotier.com.palace-2: UDP, length 137 13:30:15.328638 openvpn_Eric Out IP archlinux.palace-2 > root-zrh-01.zerotier.com.palace-2: UDP, length 137 13:30:15.328657 openvpn_Eric Out IP archlinux.33915 > root-zrh-01.zerotier.com.palace-2: UDP, length 137 13:30:15.328667 openvpn_Eric Out IP archlinux.27004 > root-zrh-01.zerotier.com.palace-2: UDP, length 137 13:30:15.329981 openvpn_Eric Out IP archlinux.palace-2 > root-sgp-01.zerotier.com.palace-2: UDP, length 137 13:30:15.329998 openvpn_Eric Out IP archlinux.33915 > root-sgp-01.zerotier.com.palace-2: UDP, length 137 13:30:15.330007 openvpn_Eric Out IP archlinux.27004 > root-sgp-01.zerotier.com.palace-2: UDP, length 137 13:30:15.332916 openvpn_Eric Out IP archlinux.palace-2 > 104.194.8.134.palace-2: UDP, length 137 13:30:15.332934 openvpn_Eric Out IP archlinux.33915 > 104.194.8.134.palace-2: UDP, length 137 13:30:15.332941 openvpn_Eric Out IP archlinux.27004 > 104.194.8.134.palace-2: UDP, length 137 As you could see, the package still using the default route table not table 101. This happens on Debian at the same time, and I think it's a problem about Linux, not just ArchLinux. I also tested passing ip -6 rule add from some ipv6 address table 101. It can work normally, that is to say, there is a matching problem with ipv4 in ip rule, but this phenomenon does not exist in ipv6. Best, *Brandon Zhi* HUIZE LTD www.huize.asia <https://huize.asia/>| www.ixp.su | Twitter This e-mail and any attachments or any reproduction of this e-mail in whatever manner are confidential and for the use of the addressee(s) only. HUIZE LTD can’t take any liability and guarantee of the text of the email message and virus.