what happens when you 'ping -M do -s 65000 -c 4 <other IBoIP system> ? Best Regards, Strahil Nikolov В понеделник, 14 декември 2020 г., 15:46:50 Гринуич+2, Patrick Bégou <patrick.begou at legi.grenoble-inp.fr> написа: Hi, I'm deploying a CentOS8 (not stream 😁) cluster and I have a question about MTU on the interfaces. I have a connectX6 Mellanox interface where I need IBoIP setup. I've setup this interface via nmcli and set the MTU to 65520 with: nmcli connection modify ib0 mtu 65520 nmcli connection up ib0 Running "nmcli connection show ib0" report: infiniband.mtu: 65520 But "ip addr show ib0" report a mtu of 2044: 6: ib0: <BROADCAST,MULTICAST,UP,LOWER_UP> *mtu 2044 *qdisc mq state UP group default qlen 256 Why ? Who is wrong (possibly me....)? Thanks Patrick _______________________________________________ CentOS mailing list CentOS at centos.org https://lists.centos.org/mailman/listinfo/centos