On Fri, 28 May 2010 14:41:46 +0300 "Ioannis Tsouvalas" <tsouval...@atic.gr> wrote:
> reply > > Stan Hoeppner put forth on 5/28/201 5:42 AM: > > >The vmxnet 'NIC' is a virtual device, strictly a software driver. > >The vmxnet driver communicates with the ESX kernel at the speed of > >system memory, which on modern servers is over 10x faster than the > >10 Gbe signaling rate. There is no such thing as "link speed" in > >this scenario as the interfaces are all software. Ethernet link > >speed, more correctly called a link pulse synchronization, is > >generated by hardware devices called PHYs. Link pulse is a hardware > >phenomenon. It doesn't exist in phantom software drivers, in this > >case the vmxnet drivers. > > >Your issue is unrelated to the vmxnet "link speed" settings, unless > >there is a bug in the vmxnet driver code. If you send an email from > >an instance of Postfix running on a Linux guest to an instance of > >Exchange running on a Windows guest, both guests running on the same > >ESX physical machine, any communication between the two MTAs will > >occur via direct memory copy. The data will never be sent to the > >physical NIC in the server. The communication takes place through > >the ESX virtual ethernet switch, which again is strictly software. > > > >-- > >Stan > > > Stan thanks for the reply, as well as the insight regarding the > difference between soft and hard nic devices. The only reason I'm > pointing out the link pulse as well as the MTU, is that my search so > far points me towards that direction. Now if there is a bug within > the driver, then I guess more communication errors would have > occurred, and the issue wouldn't be isolated on the smtp > communication. That unfortunately, leads me back to where I started, > without even some hope on getting closer to the solution. > > Looking forward to further insight, > - > Ioannis > Are there any firewalls between the Postfix and Exchange Server ? Mihira.
