very low throughput on Mac OS X

Tom Rodriguez tom.rodriguez at
Wed Aug 17 09:26:33 PDT 2016

I’ve been using open connect on Mac OS X and noticed that I’m getting much worse throughput than the same setup running on linux on a local virtual machine.  Almost an order of magnitude worse.  I’ve googled for help on the issue but without any luck, so here I am.  I’ve tried a few different command line options and adjusting the MTU but without luck.  Are there any known issues concerning this?  I do get a lot of "Failed to write incoming packet: No buffer space available” on the mac but it didn’t seem like enough to explain the low throughput.  I’m not sure what VPN hardware I’m talking to it’s connecting like so on both mac and linux.

Established DTLS connection (using GnuTLS). Ciphersuite (DTLS0.9)-(RSA)-(AES-128-CBC)-(SHA1).


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