Few packet shows as sent in wcf service traces but not received at client end for customer environment under proxy RRS feed

  • Question

  • We are witnessing an issue in one of our customer environment (configured under proxy) where in few data packets is not reaching caller environment. In the WCF trace logs we see packet being sent out of source machine but not being acknowledged at receiver end.

    Any reason why we might see this behavior, packet being shown as sent in wcf trace but not reached the consumer? Can the proxy involve in sending the packet but why it happens in regular pattern only for few packets and not for all?

    We analyzed whether size of packet cause the issue at proxy end but we have received packets of higher size than the one which is blocked.

    BTW we are using service bus relay to transmit data from customer environment to our network. Is there a way to see whether packet actually reach service bus relay based on correlationId or activityId present in WCF logs along with timestamp and service bus dns or can we achieve it through any additional logging?

    Network team from Customer side claims they have whitelisted  * DNS.

    Let me know if you need any more details.

    Thanks in advance!

    Tuesday, December 3, 2019 1:52 AM

All replies

  • Hi,

    What are the error message details the client got? Is it possible the firewall caused the loss of the packet? I am afraid that the communication over a particular port might be blocked by the intermediate device.

    I haven’t encountered this kind of issue. under what circumstances will packet loss occur?

    Best Regards


    Thursday, December 5, 2019 10:04 AM
  • Hi Abraham,

    Thanks for response. We dont see any errors in wcf logs but packet is not reaching the caller. Application is working fine in when hosted in Azure VMs and we are facing the issue when hosted in Cx environment which is under proxy. Network admin from Cx side confirmed that he couldn't see any error but couldn't confirm on number of packets sent out to make sure packet is sent out of proxy.

    The packet loss is happening for last packet.

    Tuesday, December 10, 2019 2:50 AM
  • Hi,

    Under the circumstance that there is a web proxy in the network, please refer to the below link to set up a proxy.
    I think you are right. the web proxy plays an intermediate role on transferring the data packet. There might be something wrong with proxy settings. I don’t know much about this network scenario.
    I suggest you ask your network administrator for more information.
    Best Regards

    Tuesday, December 10, 2019 7:10 AM