Hi all,
Does anyone know if FIX protocol does not work well when the TCP/IP part has a header with DF bit set to OFF?
Currently we observe an intermittent issue between server/client that pulling data using FIX . The packet capture reveals that DF flag is off. Previously in working environment, we can see that the DF bit is on in the TCP/IP header.
Any insight would be very appreciate.
Thanks
@engelhard, you didn’t explain what is meant by “does not work well”, and you didn’t specify at what point the packet capture is taken. I’m guessing that it has something to do with dropped packets since DF relates to packet fragmentation. FIX Protocol is above the transport layer and therefore has nothing to say about such issues. I recommend that you take this up with support for your TCP stack and routers.
Just to add to what @donaldmendelson said: we usually had such problems when the FIX messages exceeded a certain size (about 1400 bytes) and MTU or MSS were not matching on both sides of the connection. So maybe check that.
You should see info on the MSS in the SYN packets in the capture.