Inititally my 876 runs c870-advipservicesk9-mz.124-15.T7.bin code which runs fine. However, I once tried c870-advipservicesk9-mz.124-24.T1.bin and now c870-advipservicesk9-mz.150-1.XA3.bin and the two last ones exhibit a weird problem that may be mtu/mss related
If I revert to 124.15.T7, it works directly, the 124-24.T1 and 15--1.XA3 fail.
The configs are al the same.
Playing with vlan 1 ip tcp adjust-mss doesn't seem to help here.
Used OSes behind the router are windows vista, xp and linux and all show the same problem.