Problem:
I'm seeing this assertion when starting up the second node in a replset

Mon Sep 13 04:31:17 MongoDB starting : pid=10451 port=27000 dbpath=/var/lib/mong
odb/replset0 64-bit

• • NOTE: This is a development version (1.7.1-pre-) of MongoDB.
  • Not recommended for production.

Mon Sep 13 04:31:17 db version v1.7.1-pre-, pdfile version 4.5
Mon Sep 13 04:31:17 git version: e35a30f2b40ee9de42eef3c02e863d42b6b3b824
Mon Sep 13 04:31:17 sys info: Linux domU-12-31-39-06-79-A1 2.6.21.7-2.ec2.v1.2.f
c8xen #1 SMP Fri Nov 20 17:48:28 EST 2009 x86_64 BOOST_LIB_VERSION=1_41
Mon Sep 13 04:31:17 [initandlisten] Assertion failure get()->isReady() util/so
ck.cpp 211
0x539371 0x54520f 0x5357cc 0x672e68 0x832324 0x832cb8 0x8392f7 0x7fc69922cc4d 0x
4d0889
/var/opt/mongodb/bin/mongod(_ZN5mongo12sayDbContextEPKc+0xb1) [0x539371]
/var/opt/mongodb/bin/mongod(_ZN5mongo8assertedEPKcS1_j+0x10f) [0x54520f]
/var/opt/mongodb/bin/mongod(_ZN5mongo16ListeningSockets11listeningOnERKNS_11Hos
tAndPortE+0xadc) [0x5357cc]
/var/opt/mongodb/bin/mongod(_ZN5mongo19parseReplsetCmdLineESsRSsRSt6vectorINS_1
1HostAndPortESaIS2_EERSt3setIS2_St4lessIS2_ES3_E+0x408) [0x672e68]
/var/opt/mongodb/bin/mongod(_ZN5mongo14_initAndListenEiPKc+0x684) [0x832324]
/var/opt/mongodb/bin/mongod(_ZN5mongo13initAndListenEiPKc+0x18) [0x832cb8]
/var/opt/mongodb/bin/mongod(main+0x64d7) [0x8392f7]
/lib/libc.so.6(__libc_start_main+0xfd) [0x7fc69922cc4d]
/var/opt/mongodb/bin/mongod(__gxx_personality_v0+0x399) [0x4d0889]
Mon Sep 13 04:31:17 [initandlisten] exception in initAndListen std::exception: a
ssertion util/sock.cpp:211, terminating
Mon Sep 13 04:31:17 dbexit:
Mon Sep 13 04:31:17 [initandlisten] shutdown: going to close listening sockets..
.
Mon Sep 13 04:31:17 [initandlisten] shutdown: going to flush oplog...
Mon Sep 13 04:31:17 [initandlisten] shutdown: going to close sockets...
Mon Sep 13 04:31:17 [initandlisten] shutdown: waiting for fs preallocator...
Mon Sep 13 04:31:17 [initandlisten] shutdown: closing all files...
Mon Sep 13 04:31:17 closeAllFiles() finished

Reproduce:

• install above build

• start first node in replset with
  shell> /var/opt/mongodb/bin/mongod --port 27000 --shardsvr --replSet replset0/ --dbpath /var/lib/mongodb/replset0 --fork --logpath /var/opt/mongodb/log/server.log --logappend --rest

• startup second node in replset with
  shell> mongod --port 27000 --shardsvr --replSet replset0/10.202.215.159:27000 --dbpath /var/lib/mongodb/replset0 --fork --logpath /var/opt/mongodb/log/server.log --logappend --rest

You will see the assert in the log of the second node

Business Case:
Reliability, this works in 1.6.0