MTU traceroute and value check

check your MTU settings with user@computer:~$ tracepath -n www.cix.hr 1: 10.254.30.250 0.099ms pmtu 1500 1: 10.254.30.254 0.425ms 1: 10.254.30.254 0.405ms 2: 10.0.0.1 1.345ms 3: 212.92.211.193 4.111ms 4: 10.51.0.2 4.327ms 5: 10.50.0.74 192.967ms 6: 193.192.15.65 6.561ms asymm 7 7: 193.198.228.98 4.719ms asymm 10 8: 193.198.228.110 6.181ms asymm 9 9: 193.198.229.69 5.390ms asymm 10 10: 161.53.2.116 4.403ms

BGP session flapping

my customer is peering with 2 ISP’s and has configuration with 2 BGP routers mutually connected with iBGP. routers are reciving full tables from ISP’s and has 4 byte AS (XXXXXX). recently we noticed that BGP session between customer and ISP2 is constantly flapping each 3 minutes. logs didn’t show anything useful %BGP-4-MSGDUMP: unsupported or mal-formatted