Manufacturer application notes for 100 Mbit ethernet suggests to make the PCB traces between transformer and RJ45 connector not longer than 25 mm. In my understanding, this is mainly for interference reduction.
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The shown 4-wire connection has a transmission line impedance considerably larger than 100 ohm. I assume that it works even with 100 Mbit ethernet, but it's no good solution. Twisting the RX and TX pairs would improve the signal quality.