iax2 registration question

hello,
i have a question about the underlying functionality of IAX. I have two scenarios which achieve the same goal, but I am wondering which is the better (more reliable) method.

Method 1:
Each of my asterisk servers has a a dynamic IAX ‘friend’ specified. Something like this:

Server 1

[general]
register => AST001:asterisk@10.2.100.102

[AST002]
type=friend
host=dynamic
context=default
secret=asterisk
transfer=no

Server 2

[general]
register => AST002:asterisk@10.2.100.101

[AST001]
type=friend
host=dynamic
context=default
secret=asterisk
transfer=no

Each server knows about and registers with each other server on the network. This method works very well, but is a pain to maintain because if I add or remove a system from the topology I have to go through and update every iax.conf to account for the change.

Method 2:
Each of my asterisk servers has a static IAX ‘friend’ definition with no secret specified, but an explicit “permit” from the IP address.

[AST001]
type=friend
host=10.2.100.101
permit=10.2.100.102
context=default
transfer=no

[AST002]
type=friend
host=10.2.100.102
permit=10.2.100.102
context=default
transfer=no

The nice thing about this, is that I simply have the same iax.conf on all my servers and I don’t need to worry about the register statements.

The reason I am even bringing this is up is because the “method 1” servers all work flawlessly. They run and never throw an IAX errors. The servers I have configured with “method 2” occasionally post the following to my log files:

[Feb 16 17:57:34] WARNING[25177] chan_iax2.c: Max retries exceeded to host 10.2.252.187 on IAX2/VRU007-7269 (type = 6, subclass = 11, ts=370043, seqno=110)
[Feb 16 17:57:42] WARNING[25175] chan_iax2.c: Max retries exceeded to host 10.2.252.187 on IAX2/VRU007-7269 (type = 6, subclass = 2, ts=378022, seqno=111) 

To make a long story short… I am just wondering if these errors are generated by the method in which my IAX connections are made, or if perhaps it’s something unrelated.

thanks.
G