I saw this thread which is very similar to my issue, though I cannot solve mine with iptables. http://lists.digium.com/pipermail/asterisk-users/2013-September/280429.html Using asterisk 11.5, IAX does not seem to be able to receive any packets. My IP tables looks like this: root at dlaptop:/home/darryl# iptables -L Chain INPUT (policy ACCEPT) target prot opt source destination Chain FORWARD (policy ACCEPT) target prot opt source destination Chain OUTPUT (policy ACCEPT) target prot opt source destination could it be any simpler???? with IAX debugging on in asterisk I see this in the console: Tx-Frame Retry[000] -- OSeqno: 000 ISeqno: 000 Type: IAX Subclass: POKE Timestamp: 00015ms SCall: 00525 DCall: 00000 [184.75.215.106:4569] Tx-Frame Retry[000] -- OSeqno: 000 ISeqno: 000 Type: IAX Subclass: POKE Timestamp: 00014ms SCall: 00890 DCall: 00000 [67.205.74.184:4569] Tx-Frame Retry[001] -- OSeqno: 000 ISeqno: 000 Type: IAX Subclass: POKE Timestamp: 00010ms SCall: 05381 DCall: 00000 [99.245.204.155:4569] Tx-Frame Retry[001] -- OSeqno: 000 ISeqno: 000 Type: IAX Subclass: POKE Timestamp: 00015ms SCall: 00525 DCall: 00000 [184.75.215.106:4569] Tx-Frame Retry[001] -- OSeqno: 000 ISeqno: 000 Type: IAX Subclass: POKE Timestamp: 00014ms SCall: 00890 DCall: 00000 [67.205.74.184:4569] Notice there are no Rx-Frames, and my peer table looks like this: dlaptop*CLI> iax2 show peers Name/Username Host Mask Port Status Description voipms/121322_i 184.75.215.106 (S) 255.255.255.255 4569 UNREACHABLE voipms2/121322_ 67.205.74.184 (S) 255.255.255.255 4569 UNREACHABLE 2222/2222 99.245.204.155 (S) 255.255.255.255 4569 UNREACHABLE 3 iax2 peers [0 online, 3 offline, 0 unmonitored] tcpdump can see all the packets though: 17:23:35.840421 IP 184-75-215-106.amanah.com.iax > dlaptop-2.local.iax: UDP, length 12 17:23:35.872904 IP 67.205.74.184.iax > dlaptop-2.local.iax: UDP, length 12 17:23:36.790984 IP dlaptop-2.local.iax > CPEc47d4f8848e7-CM0026f30cc55d.cpe.net.cable.rogers.com.iax: UDP, length 14 17:23:36.792680 IP CPEc47d4f8848e7-CM0026f30cc55d.cpe.net.cable.rogers.com.iax > dlaptop-2.local.iax: UDP, length 12 17:23:36.814493 IP dlaptop-2.local.iax > 184-75-215-106.amanah.com.iax: UDP, length 14 17:23:36.834119 IP dlaptop-2.local.iax > 67.205.74.184.iax: UDP, length 14 17:23:36.842537 IP 184-75-215-106.amanah.com.iax > dlaptop-2.local.iax: UDP, length 12 17:23:36.877078 IP 67.205.74.184.iax > dlaptop-2.local.iax: UDP, length 12 17:23:43.836844 IP dlaptop-2.local.iax > CPEc47d4f8848e7-CM0026f30cc55d.cpe.net.cable.rogers.com.iax: UDP, length 24 17:23:43.838705 IP CPEc47d4f8848e7-CM0026f30cc55d.cpe.net.cable.rogers.com.iax > dlaptop-2.local.iax: UDP, length 65 but my socket buffers are backing up horribly: root at dlaptop:/home/darryl# lsof -n -P -Tq | grep UDP | grep 4569 lsof: WARNING: can't stat() fuse.gvfs-fuse-daemon file system /home/darryl/.gvfs Output information may be incomplete. asterisk 2575 root 8u IPv4 334734592 0t0 UDP *:4569 (QR=163904 QS=0) Am i crazy? Is there something as simple as iptables that I missed? Or is there some kind of bug in Asterisk which is being missed? I've only had this issue on two machines which I've compiled 11.5 on. Generally all my production machines are using the stock version 1.8 which is in the Ubuntu 12.04 repository. Unloading and reloading the chan_iax module only has the effect of resetting the receive queue size in lsof. Anyone have any ideas what I could possibly be missing here? Sip works fine by the way. Thanks Darryl