On Wed, Oct 5, 2022 at 11:15 AM Mark Fanara via curl-library <curl-library@lists.haxx.se> wrote:
> The problem turned out to be the fact that an upstream device was sending > ICMP ‘fragmentation needed’ back to me with a MTU next hop value < 576. My > newer OS apparently discarded them because of the next hop value. I was able > to change the OS path MTU behavior by setting > /proc/sys/net/ipv4/ip_no_pmtu_disc to 1 (echo ‘1’ > > /proc/sys/net/ipv4/ip_no_pmtu_disc) per > https://www.kernel.org/doc/html/latest/networking/ip-sysctl.html. Doing this will cause more trouble than what it is "solving". Unless you know exactly what you are doing and are well versed on what the linux kernel will actually do (i.e what the source code does.. and not what you interpret the documentation to do) do not fiddle with this settings and expect things to work. Anyways, this is not a Curl issue. Most of the time you do not want to change the MTU at all but use MSS clamping instead. take care. -- Unsubscribe: https://lists.haxx.se/listinfo/curl-library Etiquette: https://curl.se/mail/etiquette.html
